Solid ganaxolone formulations and methods for the making and use thereof

ABSTRACT

In certain embodiments, the invention is directed to composition comprising stable particles comprising ganaxolone, wherein the volume weighted median diameter (D50) of the particles is from about 50 nm to about 500 nm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/052,798 filed Mar. 21, 2011; which is a continuation of U.S. patentapplication Ser. No. 11/605,700 filed Nov. 28, 2006 (now U.S. Pat. No.7,858,609); which claims priority from U.S. Provisional Application No.60/758,171, filed Jan. 11, 2006; U.S. Provisional Application No.60/740,174, filed Nov. 28, 2005; and U.S. Provisional Application No.60/740,208, filed Nov. 28, 2005, the disclosures of which are all herebyincorporated by reference in their entireties for all purposes.

FIELD OF THE INVENTION

Described herein are ganaxolone formulations which provide enhancedstability, physical and chemical properties and can provide enhancedpharmacokinetic properties to achieve an optimal balance betweenpharmacodynamic and side effect profiles in mammals, and dosage formscontaining the same, as well as methods of making ganaxoloneformulations and their use in the treatment of epilepsy-related andother central nervous system disorders.

BACKGROUND OF THE INVENTION

Positive modulators of GABA_(A) receptors have long been used in thetreatment of disorders of the central nervous system, includingepilepsy, anxiety, sleep disorders, abnormal muscle tone includingspasticity, and the alcohol withdrawal syndrome (Macdonald and Olsen,1994; Mehta and Ticku, 1999; Mohler et al., 2001). Such pharmacologicalagents also have medical uses to induce anesthesia and amnesia(Chapouthier and Venault, 2002; Rudolph and Antkowiak, 2004). Typicalpositive modulators of GABA_(A) receptors include neuroactive steroids,benzodiazepines, non-benzodiazepine benzodiazepine-site agonists,barbiturates, propofol, chlormethiazol, and anesthetic agents such asetomidate, propofol, isoflurane and sevoflurane (Trapani et al., 2000;Lambert et al., 2003; Hemmings et al., 2005; Johnston, 2005; Rudolph andAntkowiak, 2005). γ-Aminobutyric acid (GABA) is the major inhibitoryneurotransmitter in the nervous system. GABA acts on several targets,including GABA_(A) receptors. GABA_(A) receptors are ionotropicreceptors that transport chloride ions across neuronal cell membranes,which induce hyperpolarization and shunts excitatory inputs, thusinhibiting the excitability of neurons. GABA_(A) receptors areheteropentamers that are generally composed of three of more differentsubunits. The subunit composition of GABA_(A) receptors is a majordeterminant of the pharmacological sensitivity of the receptor (Mohleret al., 2001; Sieghart and Sperk, 2002). For example, sensitivity tobenzodiazepines and non-benzodiazepine benzodiazepine-site agonistsrequires the presence of a γ2 subunit and there is no responsiveness ifα4 or α6 subunits substitutes for the more common α1, α2 and α3subunits. By contrast neuroactive steroids that act as GABA_(A) receptorpositive modulators do not require γ2 and are sensitive even ifreceptors contain α4 and α6 (Lambert et al., 2003). Although GABA_(A)receptors that contain the δ subunit do not respond to benzodiazepinesor benzodiazepine-site ligands, (Jones-Davis et al., 2005), they aremore sensitive to neurosteroids than are receptors containing the moreabundant γ2L subunit (Adkins et al., 2001; Brown et al., 2002; Wohlfarthet al., 2002).

Neurosteroids, and particularly ganaxolone, act on different populationsof GABA_(A) receptors than do benzodiazepines. The distribution ofbenzodiazepine sensitive GABA_(A) receptors is distinct in the brainfrom the distribution of neuroactive steroid sensitive receptors(Sieghart and Sperk, 2002). In addition, benzodiazepines enhance thephysiological activity of GABA_(A) receptors through different effectson the gating of the receptor than do neuroactive steroids (Twyman andMacdonald, 1992; Wohlfarth et al., 2002). Barbiturates actpreferentially on GABA_(A) receptors containing δ subunits as partialagonists (Feng et al., 2002, 2004). However, barbiturates, unlikebenzodiazepines and neurosteroids, act on other molecular targets thanGABA_(A) receptors, most notably voltage-dependent calcium channels(French-Mullen et al., 1993; Rudolph and Antkowiak, 2005). Thus, themajor classes of drugs that act on GABA_(A) receptors each have distinctspectrums of activity, and neuroactive steroids act on a set of targetsthat does not overlap with any other class. In addition, pharmacologicalstudies have shown that these various classes of drugs interact withheteromeric GABA_(A) receptor complexes at pharmacologicallydistinguishable sites (Lambert et al., 2003). Specifically, the actionsof neuroactive steroids occur at sites on GABA_(A) receptors that aredistinct from the site of action of benzodiazepines or barbiturates.Another important distinction between the mode of action ofbenzodiazepines and neuroactive steroids is that benzodiazepine appearsto act largely at synaptic GABA_(A) receptors and thus directly modulateinhibitory GABAergic. By contrast, neuroactive steroids may act moreprominently on extrasynaptic or perisynaptic GABA_(A) receptors that donot mediate inhibitory synaptic transmission, but rather generate atonic chloride current that sets the general level of excitability ofthe neuron (Stell et al., 2003; Ferrant and Nusser, 2005).

Neuroactive steroids have a different pattern of selectivity for thevarious GABA_(A) receptor isoforms (subunit combinations) from othertypes of positive allosteric modulators of GABA_(A) receptors. Inaddition, the functional effects of neuroactive steroids differ fromthose of other GABA_(A) receptor modulators. For example, neuroactivesteroids have greater efficacy than benzodiazepines (Kokate et al.,1994) and they act in specific ways to alter the gating of GABA_(A)receptors (Bianchi and Macdonald, 2003). Neuroactive steroids are notknown to affect other ion channels and receptor systems within the samerange of concentrations at which they affect GABA_(A) receptors, whereasother GABA_(A) receptor modulators have effects on diverse moleculartargets. An additional difference between neuroactive steroids and otherGABA_(A) receptor positive modulators is that tolerance does not occurto the anticonvulsant effects neuroactive steroids in general (Kokate etal., 1998) and the neurosteroid ganaxolone in particular (Reddy andRogawski, 2000). Tolerance does occur to the sedative effects ofganaxolone in human subjects (Monaghan et al., 1999). By contrast,tolerance develops rapidly to the sedative activity of benzodiazepinesand more slowly to their anticonvulsant activity.

Ganaxolone, a neurosteroid also known as3α-hydroxy-3β-methyl-5α-pregnan-20-one, is the 3β-methylated, syntheticanalog of the endogenous progesterone metabolite,3α-hydroxy-5α-pregnan-20-one (3α,5α-P, Allopregnanolone). It is a memberof a novel class of neuroactive steroids, which act as positiveallosteric modulators of the γ-aminobutyric (GABA_(A)) receptor complexin the central nervous system through interaction with a uniquerecognition site that is distinct from the benzodiazepine andbarbiturate binding sites (Carter et al., 1997). Ganaxolone has beenshown to exhibit potent anticonvulsant, anti-anxiety and anti-migraineactivity in preclinical models. Ganaxolone has also been shown to extendthe life of mice with a lysosomal lipid storage disease that is due todisruption of the mouse homolog of the NPC1 gene, a loci linked toNiemann Pick C in humans. In addition, ganaxolone has been usedclinically in adults for the treatment of refractory complex partialseizures and children with refractory infantile spasms and other typesof epilepsy. Appropriate ganaxolone formulations also have the potentialto treat sleep related disorders.

Ganaxolone is different from other neurosteroids in that the alcohol inthe 3 position is blocked from oxidation to the ketone. The 3-ketofunctionality imparts meaningful steroidal activity, so ganaxolone isdistinct from the endogenous neurosteroid (3α, 5α-P) which can bemetabolized in vivo to a steroid active compound. Thus, ganaxolone not asteroid and does not have to be handled with the same care andprotection as a steroid during its manufacturing and packaging.

It has been very difficult to formulate therapeutically effective dosageforms specific for neurosteroids such as ganaxolone. Ganaxolone is apoorly soluble drug that does not provide good blood levels upon oraladministration. Previous dosage forms of ganaxolone have also shownparticularly large exposure differences in fed and fasted subjects.Based upon this difficulty, there exists a need in the art for improvedganaxolone formulations and dosage forms. Herein are described soliddosage ganaxolone formulations which address this need and which provideimproved pharmacokinetic properties which maintain efficacy whilereducing side effects and enhancing subject compliance.

All references discussed herein are incorporated by reference in theirentireties for all purposes.

SUMMARY OF THE INVENTION

Described herein are compositions, pharmaceutical compositions, methodsfor treating, methods for formulating, methods for producing, methodsfor manufacturing, treatment strategies, pharmacokinetic strategiesusing ganaxolone.

In one aspect the invention provides a ganaxolone solid oral dosage formcomprising at least 200 mg ganaxolone and having a total weight of lessthan 800 mg.

A ganaxolone formulation comprised of ganaxolone containing particlescombined with a small molecule complexing agent providing addedstability and superior physical properties such as freeze/thawstability, heat stability and particle size stability. The types ofcomplexing agents are not anticipated to provide such benefit and aresmall molecules not containing a sulfonic acid or sulfonate moiety boundto less than 2 saturated carbon atoms.

A ganaxolone formulation to which an ionic dispersion modulator has beenadded to redisperse ganaxolone containing particles from a solid dosageform without substantial agglomeration.

The invention also provides a pulsatile release ganaxolone oral dosageform, comprising: (a) a first dosage unit comprising a first ganaxolonedose that is released substantially immediately following oraladministration of the dosage form to a patient; (b) a second dosage unitcomprising a second ganaxolone dose that is released approximately 3 to7 hours following administration of the dosage form to a patient.

Methods of making ganaxolone solid dosage forms including pulsatilerelease ganaxolone oral dosage forms are included herein.

The inventors have prepared stable submicron ganaxolone particles withparticularly advantageous pharmaceutical properties. Stable ganaxoloneparticles described herein comprise a complex of ganaxolone and acomplexing agent. Additional factors that affect stability and particlesize are described herein.

In one aspect are compositions comprising ganaxolone in which theganaxolone has at least one of the following properties: (a) greaterthan 90% of the ganaxolone by weight is in the form of submicronparticles; (b) at least about 20% of the ganaxolone by weight is in theform of an amorphous powder; (c) at least about 50% of the ganaxolone byweight is in the form of a crystalline powder of a single polymorph; (d)at least about 50% of the ganaxolone is in the form of asemi-crystalline powder; (e) the ganaxolone is in the form ofirregular-shaped particles; (f) the ganaxolone is in the form ofnon-uniform shaped particles; (g) at least about 80% of the ganaxolonehas the same general shape while having a distribution of particlesizes; (h) the ganaxolone is in the form of particles having a Gaussiansize distribution; (i) the ganaxolone is in the form of particles havinga non-Gaussian particle size distribution; (j) the ganaxolone is in theform of particles wherein the particle size distribution is the sum oftwo Gaussian particle size distributions; (k) the ganaxolone is in theform of particles having a multi-modal particle size distribution; (l)the ganaxolone is in the form of particles having a particle sizedistribution with a single mode; (m) the ganaxolone is in the form ofparticles wherein at least about 50% of the particles by weight have aneffective particle size less than 500 nm; (n) the ganaxolone is in theform of particles wherein at least about 60% (or at least about 70%, atleast about 80%, at least about 90%) of the particles by weight have aneffective particle size less than 1000 nm; (o) the ganaxolone is in theform of particles, wherein the particle size distribution is describedby a three-slice model in which a certain percentage has an effectiveparticle size by weight between about 10 nm and about 300 nm, a certainpercentage has an effective particle size by weight between about 300 nmand about 600 nm, and a certain percentage has an effective particlesize by weight above 600 nm, and further wherein the three-slice modelis identified as x %/y %/z %, respectively (e.g., 40%/30%/30%); (p) theganaxolone has a three-slice distribution selected from the group40%/30%/30%, 50%/30%/20%, 60%/30%/10%, 40%/40%/20%, 50%/40%/10%,70%/20%/10%, 50%/45%/5%, 70%/25%/5%, 60%/35%/5%, 80%/15%/5%, 70%/30%/0%,60%/40%/0%, 90%/10%/0%, and 100%/0%/0%; (q) the ganaxolone is in theform of particles, wherein standard deviation of the particle sizedistribution divided by the volume-weighted mean diameter is less thanabout 30%, less than about 25%, less than about 20%, less than about15%, or less than about 10%; (r) the ganaxolone is not in the form ofparticles; (s) the ganaxolone is in the form of a particle coated withanother material; (t) the ganaxolone coats at least a portion of anothermaterial; (u) the ganaxolone is microencapsulated in another material;and (v) the ganaxolone is in the form of a particle, wherein theparticle size distribution is determined by a laser-light scatteringmethod. In alternative embodiments, the ganaxolone in the compositionhas at least two of the aforementioned properties; at least about threeof the aforementioned properties; at least about four of theaforementioned properties; or at least five of the aforementionedproperties.

In another aspect are pharmaceutical formulations comprising ganaxolone,wherein the formulation has at least one of the followingcharacteristics (a) the ganaxolone is selected from one of theaforementioned compositions comprising ganaxolone; (b) the formulationis suitable for administration to a mammal; (c) the ganaxolone issuitable for administration to a human; (d) the ganaxolone is suitablefor administration to a human patient having a central-nervous systemdisease or disorder; (e) the formulation is suitable for administrationto a human less than 2 years old; (f) the formulation is suitable foradministration to a human between the ages of 2 and 16 years old; (g)the formulation is suitable for administration to an adult; (h) theformulation is suitable for administration to a pre-pubescent human; (i)the formulation is suitable for a post-pubescent human; (j) theformulation is suitable for administration to a human older than about65 years old; (k) the formulation contains pharmaceutically acceptableexcipients; (l) the formulation is suitable for administration to apatient having or expecting an epileptic seizure; (m) the formulation isin the form of a pharmaceutically-acceptable solid dosage form; (n) theformulation is in the form of a pharmaceutically-acceptable non-soliddosage form; (o) the formulation is in the form of apharmaceutically-acceptable suspension; (p) the formulation furthercomprises water; (q) the formulation further comprises apharmaceutically-acceptable viscosity-enhancing agent; (r) theformulation further comprises a dispersing agent; (s) the formulationfurther comprises a pharmaceutically-acceptable wetting agent; (t) theformulation further comprises a sweetener; (u) the formulation furthercomprises at least one preservative; (v) the formulation is suitable foradministration to a patient via a route selected from oral, intranasal,intravenous, subcutaneous, intramuscular, buccal, and transdermal; (w)the formulation is in the form of a pharmaceutically-acceptable solidoral dosage form; (x) the formulation further comprises a pH-sensitivecoating; Also add the formulation comprises a pH insensitive coating (y)the formulation is formulated for pulsatile release; (z) the formulationfurther comprises a preservative; (aa) the formulation comprises a pHindependent coating; (ab) the formulation is formulated via thespray-layering onto a sphere or bead; (ac) the formulation comprises aninhibitor of ganaxolone crystallization; (ad) the formulation is in theform of a microencapsulated drug; (ae) the formulation is in the form ofan aqueous dispersion wherein the concentration of ganaxolone is betweenabout 25 to 50 mg/ml of solution; (af) the formulation can beresuspended to a homogenous suspension by shaking; (ag) the formulationcomprises ganaxolone on an excipient bead; (ah) the formulation has anamount of ganaxolone of between about 20% to about 40% by weight; Theformulation has an amount of ganaxolone about 40% to 65% by weight (ai)the formulation is in the form of a pharmaceutically-acceptable tabletor capsule; (aj) the formulation is in the form of a solid dispersion;(ak) the formulation includes ganaxolone available for immediate releasein a patient and ganaxolone in the form of an intermediate release in apatient; The formulation includes Ganaxolone available for immediaterelease in a patient; (al) the formulation has an enteric coating; (am)the formulation is formulated for releasing greater than about 70%,about 80%, or about % of the ganaxolone dosed (by weight) in the stomachand small intestine of a patient; (an) the formulation is formulated sothat about 70%, about 80%, or about 90% of the ganaxolone particles byweight dosed are absorbed within about 6 to about 7 hours afteradministration (ao) the formulation is produced by a method comprising amilling step; (ap) the formulation is produced by a method comprising agrinding step; (aq) the formulation is produced by a method comprising aspray drying step; (ar) the formulation is produced by a methodcomprising a super-critical fluid; (as) the formulation is produced by amethod comprising a crystallization step; (at) the formulation isproduced by a method comprising a crushing step; (au) the formulation isproduced by a method comprising a communition step; (av) the formulationis produced by a method comprising a rapid expansion of supercriticalfluids step; (aw) the formulation is produced by a method comprising aultrasonication step; (ax) the formulation is produced by a methodcomprising a precipitation step; (ay) the formulation is produced by amethod comprising a fluidized bed process; (az) the formulation isproduced by a method comprising a Wurster column; (ba) the formulationis produced by a method comprising a coating step; (bb) the formulationis produced by a method comprising a supercritical fluid fracture step;(bc) the formulation is produced by a method comprising amicrofluidizer; (bd) the formulation is produced by a method comprisinga high pressure homogenization step; or (be) the formulation is formedby a method comprising a hot melt step. In alternative embodiments, theformulation has at least two of the aforementioned properties; at leastabout three of the aforementioned properties; at least about four of theaforementioned properties; at least five of the aforementionedproperties; or at least six of the aforementioned properties.

In another aspect are methods for treating a disease or disorder in apatient comprising administering a pharmaceutical formulation comprisingganaxolone, wherein the method includes at least one of the followingsteps or characteristics: (a) the patient is administered at least oneof the aforementioned ganaxolone formulations; (b) the disease ordisorder is a central nervous system disease or disorder; (c) thedisease or disorder is epilepsy; (d) the disease or disorder is aGABA-ergic related disease or disorder; (e) the disease or disorder is aneurosteroid disease or disorder; (f) the ganaxolone is administered toinduce sedation; (g) the ganaxolone is administered as ananti-convulsant agent; (h) the ganaxolone is administered as a hypnoticagent; (i) the ganaxolone is administered in a form that maintainsplasma levels of about 50 ng/ml at steady state in the patient(C_(min)); (j) the ganaxolone is administered in a form that maintainsplasma levels of about 25 ng/ml at steady state in the patient(C_(min)); (k) the ganaxolone is administered in a form that maintainsplasma levels of about 100 ng/ml at steady state in the patient(C_(min)); (l) the C_(max)/C_(min) of ganaxolone in plasma of thepatient at steady state is less than about 2.5, less than about 2.0, orless than about 1.5; (m) the AUC_(fed)/AUC_(fasted) of ganaxolone inplasma of the patient at steady state is less than about 3.0, 2.0, lessthan about 1.8, or less than about 1.5; (n) the ganaxolone isadministered as an oral suspension to infants about every 6 hours, aboutevery 8 hours, about every 12 hours, as needed; (o) the ganaxolone isadministered as an oral suspension to infants to maintain a plasma levelof ganaxolone between about 10 to 50 ng/ml of plasma (C_(min)) over an 8hour, over a 12 hour, or over a 24 hour period; (p) the ganaxolone isadministered with a rapid release component that achieves a T_(max)between about 0.5 and 2 hours; (q) the ganaxolone is administered withan extended release component that creates a second release profile atthe concentration of the initial level at T_(max), that achieves about80% of the level at T_(max), that achieves about 70% of the level atT_(max), that achieves about 60% of the level at T_(max), or thatachieves about 50% of the level at T_(max). In preferred embodiments,the ganaxolone levels is maintained such that the plasma level is lessthan about 50 ng/ml before the next dose, which can be administered, forexample, at 4 hour, 6 hour, 8 hour, 12 hour or 24 hour intervals; (r)the ganaxolone is administered with a pH dependent release componentthat produces a second drug absorption peak that is about 80% of thelevel at T_(max), that is about 70% of the level at the level atT_(max), that is about 60% the level at T_(max), or that is about 50% ofthe level at T_(max) and the ganaxolone level is maintained such thatthe plasma level is less than about 50 ng/ml before the next dose, whichcan be administered, for example, at 4 hour, 6 hour, 8 hour, 12 hour or24 hour intervals; (s) the ganaxolone is administered twice a day; (t)the ganaxolone reduces the incidence of seizures in patients; (u) theganaxolone is administered in a form with increased kinetic dissolution;(v) the ganaxolone is administered in a form and dose that providesabsorption (>70% of the weight) within about 4 to 6 hours afteradministration; (w) the ganaxolone is administered with at least oneother anti-epileptic agent; (x) the ganaxolone is administered with atleast one other anti-convulsant; (y) the ganaxolone is administered withan anti-anxiety agent; (z) the ganaxolone is used to treat infantilespasms; (aa) the ganaxolone is used to treat status epilepticus; (ab)the ganaxolone is used to treat partial seizures; (ac) the ganaxolone isused to treat a metabolic disorder; or (ad) the ganaxolone is used totreat catamenial epilepsy. In alternative embodiments, the method has atleast two of the aforementioned steps or characteristics; at least aboutthree of the aforementioned steps or characteristics; at least aboutfour of the aforementioned steps or characteristics; at least five ofthe aforementioned steps or characteristics; or at least six of theaforementioned steps or characteristics.

In certain embodiments, the present invention is directed to stableganaxolone particles utilizing a complexing agent.

In certain embodiments, the present invention is directed topharmaceutical compositions containing stable ganaxolone particlescomprising a ganaxolone complex exhibiting a ratio of D50 after storagein SGF or SIF at 36 to 38° C. for 1-3 hours to D50 prior to storage ofless than about 3:1.

In further embodiments, the invention is directed to a method of millingpharmaceutical products including a pharmaceutically active agent (e.g.,ganaxolone), optionally, a suitable amount of simethicone, milling beadsand optional pharmaceutically acceptable excipients into a mill; andmilling the mixture for a suitable time to obtain submicron particles.

In still further embodiments, the invention is directed to apharmaceutical composition comprising particles comprising ganaxolonethereof, and simethicone, in an amount, e.g., from about 0.0001% toabout 0.1%, based on the total weight of the composition.

Another aspect of the invention is directed to a pharmaceuticalcomposition comprising ganaxolone particles thereof and a vinyl polymer,the particles having a D50 of less than about 500 nm, wherein theC_(max) and AUC_((0-τ)) after administration of the composition aredecreased as compared to the composition without the vinyl polymer.

In other embodiments, the invention is directed to a pharmaceuticalcomposition comprising particles comprising ganaxolone, the compositionproviding an increased AUC_((0-τ)) in the fasted state.

In further embodiments, the invention is directed to a pharmaceuticalcomposition comprising particles comprising ganaxolone, the compositionproviding an increased C_(max) in the fasted state.

In another aspect, the invention is directed to a pharmaceuticalcomposition comprising particles comprising ganaxolone, the compositionproviding a mean blood plasma AUC₍₀₋₂₄₎ from about 100 to about 300ng*h/mL after 200 to about 500 mg of ganaxolone is administered to adultsubjects in the fasted state.

In still another aspect, the invention is directed to a pharmaceuticalcomposition comprising particles comprising ganaxolone, the compositionproviding a mean blood plasma C_(max) from about 20 to about 85 ng/mLafter 200 to 500 mg of ganaxolone is administered to adult subjects inthe fasted state.

In yet another aspect, the invention is directed to a pharmaceuticalcomposition comprising particles comprising ganaxolone, the compositionproviding a mean blood plasma AUC₍₀₋₂₄₎ from about 300 to about 1200ng*h/mL after 200 to about 500 mg of ganaxolone is administered to adultsubjects in the fed state.

In a further aspect, the invention is directed to a pharmaceuticalcomposition comprising particles comprising ganaxolone, the compositionproviding a mean blood plasma C_(max) from about 60 to about 350 ng/mLafter 200 to 500 mg of ganaxolone is administered to adult subjects inthe fed state.

In another embodiment, the invention is directed to pharmaceuticalparticles comprising an active agent (e.g., ganaxolone); the particlesmilled for a sufficient time for the particles to provide a ratio of D50four weeks after milling to D50 at the end of milling of 1.5:1 or less.

In certain embodiments, the invention is directed to a compositioncomprising particles comprising ganaxolone, wherein the volume weightedmedian diameter (D50) of the particles is from about 50 nm to about 500nm. The composition can have at least one excipient selected from thegroup consisting of a hydrophilic polymer, a wetting agent, a complexingagent, an ionic dispersion modulator, a water soluble spacer, and amixture thereof.

In certain embodiments, the invention is directed to a compositioncomprising particles comprising ganaxolone; and an effective amount of acomplexing agent to stabilize the particle growth after an initialparticle growth and endpoint is reached, wherein the volume weightedmedian diameter (D50) of the particles before the initial growth is fromabout 50 to about 200 nm and the D50 after the endpoint is reached isfrom about 100 nm to about 350 nm.

In certain embodiments, the invention is directed to a compositioncomprising particles comprising ganaxolone; and an effective amount ofan ionic dispersion modulator to reduce agglomeration of the particles,wherein the volume weighted median diameter (D50) of the particles isfrom about 50 nm to about 350 nm.

In certain embodiments, the invention is directed to a compositioncomprising particles comprising ganaxolone; and a complexing agent in anamount of from about 0.1% to about 5%, w/w, based on the weight of thecomposition, wherein the volume weighted median (D50) of the particlesis from about 50 nm to about 350 nm.

In certain embodiments, the invention is directed to a compositioncomprising particles comprising ganaxolone; and an ionic dispersionmodulator in an amount of from about 1% to about 50%, w/w, based on theweight of the composition, wherein the volume weighted median diameter(D50) of the particles is from about 50 nm to about 350 nm.

In other embodiments, the invention is directed to a compositioncomprising particles comprising ganaxolone; a hydrophilic polymer; and awetting agent, wherein the volume weighted median diameter (D50) of theparticles is from about 50 nm to about 500 nm.

In further embodiments, the invention is directed to a compositioncomprising particles comprising ganaxolone; a hydrophilic polymer; awetting agent; and a complexing agent, wherein the volume weightedmedian diameter (D50) of the particles is from about 50 nm to about 500nm.

In still other embodiments, the invention is directed to a compositioncomprising particles comprising ganaxolone; a hydrophilic polymer; awetting agent; a complexing agent; and an ionic dispersion modulator.

In certain embodiments, the invention is directed to a compositioncomprising particles comprising ganaxolone in an amount from about 10%to about 80%, w/w, based on the total weight of the composition; ahydrophilic polymer in an amount from about 3% to about 50%, w/w, basedon the weight of the composition; a wetting agent in an amount fromabout 0.05% to about 2%, w/w, based on the weight of the composition; acomplexing agent in an amount from about 0.1% to about 5%, w/w, based onthe weight of the composition; and an ionic dispersion modulator in anamount from about 1% to about 50%, w/w, based on the weight of thecomposition.

In certain embodiments, the invention is directed to a solid formulation(e.g., a powder, immediate release dosage form, or controlled releasedosage form) comprising stable ganaxolone particles and at least onepharmaceutically acceptable excipient, the stable ganaxolone particlesexhibiting an increase in volume weighted median diameter (D50) of from0% to not more than about 200%, not more than about 150%, not more thanabout 100%, or not more than about 50%, when the formulation isdispersed in simulated gastric fluid (SGF) or simulated intestinal fluid(SIF) at a concentration of 0.5 to 1 mg ganaxolone/mL (in any suitablevolume, e.g., 15 mL to 1000 mL) and placed in a heated bath at 36° to38° C. for 1 hour, as compared to the D50 of the ganaxolone particleswhen the formulation is dispersed in distilled water under the sameconditions, wherein the volume weighted median diameter (D50) of theganaxolone particles dispersed in distilled water is from about 50 nm toabout 1000 nm, from about 100 nm to about 500 nm, or from about 100 nmto about 350 nm. The solid formulation can be, for example, a powder, atablet, a capsule, etc.

In certain aspects, the solid formulation is in the form of a tablet orcapsule containing the stable ganaxolone particles and at least oneexcipient, the stable ganaxolone particles exhibiting an increase involume weighted median diameter (D50) of from 0% to not more than about200%, not more than about 150%, not more than about 100%, or not morethan about 50%, when the tablets or capsules are dispersed in SGF or SIF(in any suitable volume, e.g., 15 mL to 1000 mL) at a concentration of0.5 to 1 mg ganaxolone/mL at 36° to 38° C. using a Type II dissolutionapparatus and a stirring rate of 75 RPM for 1 hour, as compared to theD50 of the ganaxolone particles when the tablets or capsules aredispersed in distilled water under the same conditions, wherein thevolume weighted median diameter (D50) of the ganaxolone particles whenthe tablets or capsules are dispersed in distilled water is from about50 nm to about 1000 nm, from about 100 nm to about 500 nm, or from about100 nm to about 350 nm.

In other aspects, the invention is directed to a solid formulation(e.g., a powder, immediate release dosage form, or controlled releasedosage form) comprising stable ganaxolone particles and at least onepharmaceutically acceptable excipient, the stable ganaxolone particlesexhibiting a volume weighted median diameter (D50) of less than about750 nm when the formulation is dispersed in simulated gastric fluid(SGF) for one hour followed by simulated intestinal fluid (SIF) forthree additional hours, at a concentration of 0.5 to 1 mg ganaxolone/mL(in any suitable volume, e.g., 15 mL to 1000 mL) at a temperature of 36°to 38° C.

In still other aspects, the solid formulation is a tablet or capsulecontaining the stable ganaxolone particles and at least one excipient,the stable ganaxolone particles exhibiting a volume weighted mediandiameter (D50) of less than about 750 nm when the tablets or capsulesare dispersed in simulated gastric fluid (SGF) for one hour followed bysimulated intestinal fluid (SIF) for three additional hours, at aconcentration of 0.5 to 1 mg ganaxolone/mL (in any suitable volume,e.g., 15 mL to 1000 mL) at a temperature of 36° to 38° C. using a TypeII dissolution apparatus and a stirring rate of 75 RPM.

In certain embodiments, the stable particles are prepared by contactingganaxolone particles with excipient such that the size of the particlesexhibits an increase in volume weighted median diameter of from about20% to about 300% and an endpoint is reached such that the particles arestable. The endpoint can be, e.g., from about 1 to about 20 days.

In other aspects, the invention is directed to an oral solid dosage formcomprising (i) a controlled release component comprising a first portionof particles comprising ganaxolone; and a controlled release material,and (ii) an immediate release component comprising a second portion ofparticles comprising ganaxolone, the first and second portion ofganaxolone particles having a volume weighted median diameter (D50) offrom about 50 nm to about 1000 nm, from about 100 nm to about 450 nm, orfrom about 100 nm to about 350 nm. The ratio of ganaxolone in controlledrelease to immediate release can be, e.g., from about 4:1 to about 1:4,from about 3:2 to about 2:3, or about 1:1. The controlled releasecomponent can be in any form, including but not limited to (i) aplurality of pharmaceutically acceptable beads coated with the firstportion of ganaxolone particles and overcoated with the controlledrelease material (optionally a film coat comprising a material such ashydroxypropylmethylcellulse or polyvinyl alcohol can be included on thebeads prior to coating with the ganaxolone particles), (ii) a pluralityof matrices comprising the first portion of ganaxolone particlesdispersed in the controlled release material, (iii) a tablet comprisingthe first portion of ganaxolone particles dispersed in the controlledrelease material, or (iv) a granulation comprising the first portion ofganaxolone particles and the controlled release material. The immediaterelease component can be in any form, including bit not limited to (i)plurality of pharmaceutically acceptable beads coated with the secondportion of ganaxolone particles, (ii) a plurality of matrices comprisingthe second portion of ganaxolone particles dispersed in an excipient,(iii) a tablet comprising the second portion of ganaxolone particlesdispersed in excipient, or (v) a granulation comprising the secondportion of ganaxolone particles and excipient. Alternatively, theimmediate release component can be included in the dosage form in powderform.

In certain embodiments, the controlled release component and theimmediate release component are contained in a capsule.

In other embodiments, the controlled release component is a tablet andthe immediate release component is coated onto the tablet.

In further embodiments, the controlled release component and theimmediate release component are in a bi-layer tablet.

In still other embodiments, the controlled release component comprises aplurality of pharmaceutically acceptable beads coated with the firstportion of ganaxolone particles and overcoated with the controlledrelease material and the immediate release component comprises aplurality of pharmaceutically acceptable beads coated with the secondportion of ganaxolone particles, the controlled release component andimmediate release component contained in a capsule.

In another aspect, the controlled release component comprises aplurality of pharmaceutically acceptable beads coated with the firstportion of ganaxolone particles and overcoated with the controlledrelease material and the immediate release component comprises a tabletcomprising the second portion of ganaxolone particles dispersed in anexcipient, the controlled release component and immediate releasecomponent contained in a capsule.

In still another embodiments, controlled release component comprises aplurality of pharmaceutically acceptable beads coated with the firstportion of ganaxolone particles and overcoated with the controlledrelease material and the immediate release component comprises agranulation comprising the second portion of ganaxolone particles and anexcipient, the controlled release component and immediate releasecomponent contained in a capsule.

In another embodiment, the controlled release component comprises aplurality of pharmaceutically acceptable beads coated with the firstportion of ganaxolone particles and overcoated with the controlledrelease material, and the immediate release component comprises agranulation comprising the second portion of ganaxolone particles and anexcipient, the controlled release component dispersed in the immediaterelease component in the form of a compressed tablet.

In further embodiments, the controlled release component comprises acompressed tablet and the immediate release component is compressioncoated over the controlled release tablet.

In certain embodiments, the dosage forms of the present inventionprovide pulsatile release of two or more doses of ganaxolone. The dosageform can provide an immediate release dose after administration and atleast one additional dose at a time after administration selected fromthe group consisting of 3-8 hours, 6-10 hours, 10-14 hours, 14-18 hours,16-20 hours and 22-24 hours.

In certain embodiments, the invention is directed to an oral soliddosage form comprising ganaxolone particles and a controlled releasematerial, the ganaxolone particles having a volume weighted mediandiameter (D50) of from about 50 nm to about 1000 nm, the dosage formproviding a controlled release of the ganaxolone to provide atherapeutic effect for about 8 to about 24 hours after administration.

In other embodiments, the invention is directed to an oral solid dosageform comprising particles comprising ganaxolone; and a pH dependentpolymer, the ganaxolone particles having a volume weighted mediandiameter (D50) from about 50 nm to about 1000 nm, the dosage formproviding a delayed release of the ganaxolone for a time period fromabout 2 to about 12 hours after administration.

In certain aspects, the invention is directed to a stable solid doseformulation comprising a plurality of substrates coated with particlescomprising ganaxolone; and at least one pharmaceutically acceptableexcipient, the particles having a volume weighted median diameter (D50)from about 50 nm to about 1000 nm, from about 100 nm to about 450 nm, orfrom about 100 nm to about 350 nm, the coated substrates exhibiting anincrease in volume weighted median diameter (D50) of 0 to less than 200%after being dispersed in SGF or SIF in a concentration of 0.5-1 mgganaxolone/ml and placed in a heated bath at 36° to 38° C. withoutstirring for 1 hour as compared to the D50 under the same conditionsafter being dispersed in distilled water. The volume weighted mediandiameter (D50) of the coated beads prior to dispersion can be, e.g.,from about 0.1 mm to about 5.0 mm.

In other aspects, the invention is directed to an immediate release oralsolid dosage form comprising ganaxolone particles; and at least onepharmaceutically acceptable excipient, the ganaxolone particles having avolume weighted median diameter (D50) of from about 50 nm to about 1000nm.

In certain embodiments, the invention is directed to a pharmaceuticaldosage form (e.g., a liquid or solid dosage form) comprising particlescomprising ganaxolone; and at least one pharmaceutically acceptableexcipient, the particles having a volume weighted median diameter (D50)from about 50 nm to about 1000 nm, the dosage form providing a ratio ofmean blood plasma fed AUC_((0-τ)) to fasted AUC_((0-τ)) from about 1:1to about 4:1, from about 1.3:1 to about 4:1, or from about 1:1 to about3:1.

In other embodiments, the invention is directed to a pharmaceuticaldosage form (e.g., a liquid or solid dosage form) comprising particlescomprising ganaxolone; and at least one pharmaceutically acceptableexcipient, the particles having a volume weighted median diameter (D50)from about 50 nm to about 1000 nm, the dosage form providing a ratio ofmean blood plasma fed Cmax to fasted Cmax from about 1.5:1 to about 7:1,from about 2.5:1 to about 7:1, or from about 1.5:1 to about 4:1.

In other embodiments, the invention is directed to a pharmaceuticaldosage form comprising particles comprising ganaxolone; and at least onepharmaceutically acceptable excipient, the particles having a volumeweighted median diameter (D50) from about 50 nm to about 1000 nm, thedosage form providing a mean blood plasma AUC 0-24 hours from about 100to about 375 ng*h/ml when a dose of 200 mg to 500 mg of the ganaxoloneis orally administered to adult subjects in the fasted state.

In further embodiments, the invention is directed to a pharmaceuticaldosage form comprising particles comprising ganaxolone; and at least onepharmaceutically acceptable excipient, the particles having a volumeweighted median diameter (D50) from about 50 nm to about 1000 nm, thedosage form providing a mean blood plasma Cmax from about 25 to about 70ng/ml when a dose of 200 mg to 500 mg of the ganaxolone is orallyadministered to adult subjects in the fasted state.

In yet another embodiment, the invention is directed to a pharmaceuticaldosage form comprising particles comprising ganaxolone; and at least onepharmaceutically acceptable excipient, the particles having a volumeweighted median diameter (D50) from about 50 nm to about 1000 nm, thedosage form providing a mean blood plasma AUC (0-48) hours from about400 to about 1200 ng*h/ml when a dose of 200 mg to 500 mg of theganaxolone is orally administered to adult subjects in the fed state.

In further embodiments, the invention is directed to a pharmaceuticaldosage form comprising particles comprising ganaxolone; and at least onepharmaceutically acceptable excipient, the particles having a volumeweighted median diameter (D50) from about 50 nm to about 1000 nm, thedosage form providing a mean blood plasma Cmax from about 60 to about250 ng/ml when a dose of 200 mg to 500 mg of the ganaxolone is orallyadministered to adult subjects in the fed state.

In other aspects, the invention is directed to a pharmaceutical dosageform comprising particles comprising ganaxolone; and at least onepharmaceutically acceptable excipient, the particles having a volumeweighted median of from about 50 nm to about 1000 nm, the dosage formproviding a mean blood plasma Cmax/Cmin ratio of not greater than about4 to 1 at steady state with a dose of 200 to 500 mg ganaxolone to adultsubjects in the fed or fasted state.

In still other aspects, the invention is directed to a liquidpharmaceutical dosage form comprising particles comprising ganaxolone;and at least one pharmaceutically acceptable excipient, the particleshaving a volume weighted median of from about 50 nm to about 1000 nm,the dosage form providing a mean blood plasma Cmin value of about 10-40ng/ml in infants (greater than 4 months old but less than 2 years old)at a ganaxolone dose of about 10 mg/kg at steady state.

In still other aspects, the invention is directed to a liquidpharmaceutical oral suspension comprising ganaxolone, the suspensionproviding a mean blood plasma Cmax of about 30 to 45 ng/mL and a meanblood plasma AUC (0-24) of about 160 to about 210 ng*h/mL, based on adose of 200 mg ganaxolone to subjects in the fasted state, or a meanblood plasma Cmax of about 37 ng/mL and a mean blood plasma AUC (0-24)of about 185 ng*h/mL, based on a dose of 200 mg ganaxolone to subjectsin the fasted state.

In certain embodiments, the invention is directed to an oral liquiddosage form comprising stable ganaxolone particles and at least onepharmaceutically acceptable excipient, the particles suspended in apharmaceutically acceptable liquid vehicle, wherein the volume weightedmedian diameter (D50) of the stable ganaxolone particles does not changeby more than about 15% after 10 days storage at room temperature, bymore than about 12% after 10 days storage at room temperature, by morethan about 10% after 10 days storage at room temperature, by more thanabout 8% after 10 days storage at room temperature, by more than about15% after 20 days of storage at room temperature, by more than about 15%after 40 days of storage at room temperature, by more than about 15%after 60 days of storage at room temperature, or by more than about 15%after 80 days of storage at room temperature. In certain aspects, thevolume weighted median diameter (D50) of the stable ganaxolone particlesprior to storage is from about 100 nm to about 450 nm, or from about 100nm to about 350 nm.

In certain embodiments, the invention is directed to an oral liquiddosage form wherein the volume weighted median diameter (D50) of thestable ganaxolone particles does not change by more than about 15% whenplaced in a glass vial and heated in a 100° C. oil bath for 20 minutes,does not change by more than about 15% when placed in a glass vial andheated in a 100° C. oil bath for 4 hours, does not change by more thanabout 10% when placed in a glass vial and heated in a 100° C. oil bathfor 20 minutes, does not change by more than about 5% when placed in aglass vial and heated in a 100° C. oil bath for 20 minutes, or does notchange by more than about 3% when placed in a glass vial and heated in a100° C. oil bath for 20 minutes.

In still further embodiments, the invention is directed to an oralliquid dosage form the volume weighted median diameter (D50) of thestable ganaxolone particles does not change by more than about 25% whenplaced in a HDPE container and frozen and thawed three or more timeswith the time frozen for each cycle being at least 12 hours. The frozentemperature can be any suitable freezing temperature, e.g., from about−80° C. to about −20° C. the invention is also directed to the liquiddosage forms in frozen form.

In certain embodiments, the oral liquid dosage form is prepared bycontacting ganaxolone particles with the excipient, wherein the size ofthe particles exhibits an increase in volume weighted median diameter(D50) of from about 20% to about 300% and reaching an endpoint such thatthe particles are stable.

In other aspects, the invention is directed to pharmaceutical particlescomprising ganaxolone or a pharmaceutically acceptable salt thereof, theparticles being stable such that the volume weighted median diameter(D50) of the particles does not increase by more than about 50% after 28days storage at room temperature and ambient conditions, the volumeweighted median diameter (D50) of the particles prior to storage beingfrom about 50 nm to about 1000 nm; the particles milled for a sufficienttime to achieve the stability. In other aspects, the volume weightedmedian diameter (D50) of the particles does not change by more thanabout 25% after 28 days storage at room temperature and ambientconditions, does not change by more than about 15% after 28 days storageat room temperature and ambient conditions, does not change by more thanabout 10% after 28 days storage at room temperature and ambientconditions, or does not change by more than about 50% after 40 daysstorage at room temperature and ambient conditions.

The present invention is also directed to a method of stabilizing theparticle growth of pharmaceutical particles comprising millingganaxolone to a volume weighted median diameter (D50) from about 50 nmto about 1000 nm and for a sufficient time such that that the volumeweighted median diameter (D50) of the particles does not change by morethan about 50% after 28 days storage at room temperature and ambientconditions, does not change by more than about 25% after 28 days storageat room temperature and ambient conditions, does not change by more thanabout 15% after 28 days storage at room temperature and ambientconditions, or does not change by more than about 10% after 28 daysstorage at room temperature and ambient conditions.

In still further embodiments, the present invention is directed to apharmaceutical composition comprising particles comprising (i)ganaxolone or a pharmaceutically acceptable salt thereof, and (ii) atrace amount of simethicone, the particles having a volume weightedmedian diameter (D50) of from about 50 nm to about 1000 nm. In certainembodiments, the simethicone is in an amount from about 0.001% to about1%, or 0.005% to about 0.02% simethicone, w/w, based on the weight ofthe particles.

In other embodiments, the invention is directed to a method of millingganaxolone, comprising incorporating ganaxolone, a suitable amount ofsimethicone, milling beads and optional pharmaceutically acceptableexcipients into a mill; and milling the mixture for a suitable time toobtain nanosized particles. The simethicone can be in the form of anemulsion, e.g., containing from 20% to 50% simethicone. Further, theamount of simethicone present in the milling slurry can be, e.g., fromabout 0.01% to about 5%, from about 0.02% to about 1%, or about 0.04% toabout 0.6%, w/w, based on the weight of the ganaxolone.

The present invention is also directed to a method of stabilizingpharmaceutical particles comprising preparing particles comprisingganaxolone or a pharmaceutically acceptable salt thereof having a volumeweighted median diameter (D50) about 50 nm to about 450 nm, contactingthe ganaxolone particles with a complexing agent wherein the volumeweighted median diameter (D50) of the particles increases from about 20%to about 300%, and reaching an endpoint such that the particles arestable. In further embodiments, the complexed particles are subjected tosonification to decrease the volume weighted median diameter (D50) fromabout 10% to about 60% prior to reaching the endpoint.

The present invention is also directed to a method of preparingpharmaceutical particles comprising preparing particles comprisingganaxolone or a pharmaceutically acceptable salt thereof having a volumeweighted median diameter (D50) of about 50 nm to about 450 nm, andcontacting a vinyl polymer with the ganaxolone particles such that theCmax provided by the particles is reduced from about 25% to 80%.

The present invention is also directed to a method of preparingpharmaceutical particles comprising preparing particles comprisingganaxolone or a pharmaceutically acceptable salt thereof having a volumeweighted median diameter (D50) of about 50 nm to about 450 nm, andcontacting a vinyl polymer with the ganaxolone particles such that theAUC provided by the particles is reduced from about 25% to 80%.

The present invention is further directed to methods of preparing thecompositions disclosed herein, including but not limited to, ganaxoloneparticles, liquid formulations, and oral solid dosage forms (e.g.,immediate release, sustained release, delayed release and pulsatilerelease).

The present invention is also directed to methods of treating subjectscomprising administering to a subject any of the compositions disclosedherein, including, but not limited to, ganaxolone particles, liquidformulations, and oral solid dosage forms (e.g., immediate release,sustained release, delayed release and pulsatile release).

In the above embodiments, the ganaxolone compositions of the presentinvention, (e.g., liquid or solid) comprise an excipient selected fromthe group consisting of a hydrophilic polymer, a wetting agent, acomplexing agent, an ionic dispersion modulator, a water soluble spacer,and a mixture thereof.

In certain embodiments, the excipient comprises a complexing agent. Thecomplexing agent can be a substance containing a phenol moiety, anaromatic ester moiety or an aromatic acid moiety. Particular complexingagents are selected from the group consisting of parabens, organicacids, carboxylic acids, aromatic acids, aromatic esters, acid salts ofamino acids, methyl anthranilate, sodium metabisulphite, ascorbic acidand its derivatives, malic acid, isoascorbic acid, citric acid, tartaricacid, sodium sulphite, sodium bisulphate, tocopherol, water- andfat-soluble derivatives of tocopherol, sulphites, bisulphites andhydrogen sulphites, para-aminobenzoic acid and esters,2,6-di-t-butyl-alpha-dimethylamino-p-cresol, t-butylhydroquinone,di-t-amylhydroquinone, di-t-butylhydroquinone, butylhydroxytoluene(BHT), butylhydroxyanisole (BHA), pyrocatechol, pyrogallol,propyl/gallate, nordihydroguaiaretic acid, phosphoric acids, sorbic andbenzoic acids, esters, ascorbyl palmitate, derivatives and isomericcompounds thereof, pharmaceutically acceptable salts thereof, andmixtures thereof.

In certain embodiments, the excipient comprising a hydrophilic polymer.The hydrophilic polymer can be selected from the group consisting of acellulosic polymer, a vinyl polymer and mixtures thereof. Particularhydrophilic polymers include cellulosic polymer such as cellulose ethers(e.g., hydroxypropymethylcellulose.) or a vinyl polymer such aspolyvinyl alcohol.

In certain embodiments, the excipient comprises a wetting agent. Thewetting agent can be selected from the group consisting of sodium laurylsulfate, a pharmaceutically acceptable salt of docusate, and mixturesthereof.

In certain embodiments, the excipient comprises an ionic dispersionmodulator. The ionic dispersion modulator can be a salt such as anorganic or inorganic salt. The inorganic salt can be selected from thegroup consisting of a magnesium salt, a calcium salt, a lithium salt, apotassium salt, a sodium salt and mixtures thereof and the organic saltcan be selected from the group consisting of a citrate salt, a succinatesalt, a fumarate salt, a malate salt, maleate salt, a tartrate salt, aglutarate salt, a lactate salt and mixtures thereof.

In certain embodiments, the excipient comprises a water soluble spacer.The water soluble can be a saccharide or an ammonium salt. Thesaccharide can be selected from the group consisting of fructose,sucrose, glucose, lactose, mannitol and mixtures thereof.

In embodiments directed to solid formulations, the complexing agent canbe in an amount from about 0.05% to about 5%, w/w, based on the weightof the solid formulation; the hydrophilic polymer can be in an amountfrom about 3% to about 50%, w/w, based on the weight of the solidformulation; the cellulose ether can be in an amount from about 3% toabout 50%, w/w, based on the weight of the solid formulation; thepolyvinyl alcohol van be in an amount from about 0.1% to about 5%, w/w,based on the weight of the solid formulation; the wetting agent can bein an amount from about 0.01% to about 10%, w/w, based on the weight ofthe solid formulation; the ionic dispersion modulator can be in anamount from about 1% to about 50%, w/w, based on the weight of the solidformulation; and the water soluble spacer can be in an amount from about2% to about 60%, w/w, based on the weight of the solid formulation. The% weights are not meant to be limiting.

In embodiments directed to ganaxolone coated beads, controlled releasematerial can be coated onto the drug layered bead in an amount, e.g.,from about 3% to about 25%, or from about 8% to about 12%, based on thetotal weight of the component.

In certain solid formulations, the ganaxolone particles are dispersed ina liquid to form a suspension and the suspension is spray coated ontothe plurality of substrates, or spray granulated with the plurality ofsubstrates. In further embodiments the ganaxolone particles aredispersed in a liquid to form a suspension and the suspension is spraydried to form a powder which is coated onto the plurality of substrates.The suspension can be, e.g., about 5% to about 35%, or about 15% toabout 25% total solids. The ganaxolone concentration in the solids canbe, e.g., from about 50% to about 75%.

In embodiments directed to solid dosage forms utilizing substrates, thesubstrates can be, e.g., inert beads, or can be selected from the groupconsisting of lactose, calcium carbonate, calcium phosphate, dibasiccalcium phosphate, calcium sulfate, microcrystalline cellulose,cellulose powder, dextrose, dextrates, dextran, starches, pregelatinizedstarch, sucrose, xylitol, lactitol, mannitol, sorbitol, sodium chloride,polyethylene glycol and mixtures thereof.

In embodiments directed to sustained or delayed dosage forms, the dosageform can be a granulation comprising the ganaxolone particles and thecontrolled release material, (e.g., hydrophobic polymer or pH dependentmaterial), the granulation compressed into a tablet or filled into acapsule.

In other embodiments directed to sustained or delayed release dosageforms, the dosage form can be a plurality of pharmaceutically acceptablebeads coated with the ganaxolone particles and overcoated with thecontrolled release material, (e.g., hydrophobic polymer or pH dependentmaterial), the overcoated beads compressed into a tablet or filled intoa capsule.

In embodiments directed to liquid dosage forms, the liquid dosage formcan be include at least one excipient selected from polyvinyl alcohol,sodium lauryl sulfate, methylparaben, propylparaben, sodium benzoate,citric acid, sodium citrate, simethicone, sucralose and flavoring. Forexample, the liquid dosage form can comprise about 5% ganaxolone, about1% polyvinyl alcohol, about 0.1% sodium lauryl sulfate, about 0.1%methylparaben, about 0.02% propylparaben, about 0.9% sodium benzoate,about 0.12% citric acid, about 0.06% sodium citrate, about 0.01%simethicone, about 0.02% sucralose, and flavoring. These ingredients and% amounts are not meant to be limiting.

In certain embodiments, the invention is directed to an oral liquiddosage form comprising stable ganaxolone particles,hydroxymethylpropylcellulose, sodium lauryl sulfate, simethicone,sucralose, methylparaben, propylparaben, sodium benzoate, citric acid,sodium citrate, and flavoring, the liquid having a pH of from about 3.8to about 4.2

In certain embodiments, the invention is directed to an oral liquiddosage form comprising from about 2.5% to about 5% stable ganaxoloneparticles, from about 2% to about 5% hydroxymethylpropylcellulose, fromabout 0.1% to about 0.03% sodium lauryl sulfate, from about 0.005% toabout 0.02% simethicone, from about 0.01% to about 0.03% sucralose, fromabout 0.05% to about 0.1% methylparaben, from about 0.01% to about 0.02%propylparaben, from about 0.05% to about 0.1% sodium benzoate, fromabout 0.1% to about 0.15% citric acid, from about 0.05 to about 0.1%sodium citrate and from about 0.002% to about 0.004% flavoring, theliquid having a pH of about 3.8 to about 4.2, wherein all percentagesare weight percent to the total liquid formulation weight.

In certain embodiments, the invention is directed to an oral liquiddosage form comprising stable ganaxolone particles,hydroxymethylpropylcellulose, polyvinyl alcohol, sodium lauryl sulfate,simethicone, sucralose, methylparaben, propylparaben, sodium benzoate,citric acid, sodium citrate and flavoring, the liquid having a pH ofabout 3.8 to about 4.2, wherein all percentages are weight percent tothe total liquid formulation weight.

In certain embodiments, the invention is directed to an oral liquiddosage form comprising from about 2.5% to about 5% stable ganaxoloneparticles, from about 2% to about 5% hydroxymethylpropylcellulose, about0.5% to about 1.5% polyvinyl alcohol, from about 0.1% to about 0.03%sodium lauryl sulfate, from about 0.005% to about 0.02% simethicone,from about 0.01% to about 0.03% sucralose, from about 0.05% to about0.1% methylparaben, from about 0.01% to about 0.02% propylparaben, fromabout 0.05 to about 0.1% sodium benzoate, from about 0.05% to about0.15% citric acid, from about 0.05 to about 0.1% sodium citrate and fromabout 0.002% to about 0.004% flavoring, the liquid having a pH of about3.8 to about 4.2, wherein all percentages are weight percent to thetotal liquid formulation weight.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Curing of parabens preserved and sodium benzoate preservedganaxolone particles: particle size growth was partially reversed by 1min sonication (low power setting) in the early stage of the curingprocess.

FIG. 2. Curing of parabens preserved and sodium benzoate preservedganaxolone particles: particles containing parabens were fully curedwithin 5-7 days while sodium benzoate preserved particles requiredapproximately 3 weeks to become stable.

FIG. 3. Stability plots (D50 vs time) of ganaxolone particles containingno complexing agent: ganaxolone particles without a complexing agentthat were milled for less than 2 hours of milling residence timecontinued to increase gradually in size over a number of months, whilethe particles milled for more than 2 hours of residence time did notchange over six months.

FIG. 4. Progress of a milling run using a DYNO-Mill KDL equipped withfour 64 mm polyurethane agitator discs followed by particle sizemeasurement (D50) as a function of residence time.

FIG. 5. Particle Size Distribution (after 1 minute low power sonication)of Re-suspended Solid Dosage Forms Containing Sodium Chloride: With andWithout a Complexing Agent (Methylparaben)

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to embodiments of the compositions,formulations, and methods disclosed herein. Examples of the embodimentsare illustrated in the following Examples section.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart to which the inventions described herein belong. All patents andpublications referred to herein are incorporated by reference.

CERTAIN DEFINITIONS

As used herein, the terms “comprising,” “including,”, “containing” and“such as” are used in their open, non-limiting sense.

The term “about” is used synonymously with the term “approximately.” Asone of ordinary skill in the art would understand, the exact boundary of“about” will depend on the component of the composition. Illustratively,the use of the term “about” indicates that values slightly outside thecited values, i.e., plus or minus 0.1% to 10%, which are also effectiveand safe. Thus compositions slightly outside the cited ranges are alsoencompassed by the scope of the present claims.

“Antifoaming agents” reduce foaming during processing which can resultin coagulation of aqueous dispersions, bubbles in the finished form, orgenerally impair processing. Exemplary anti-foaming agents includesilicon emulsions or sorbitan sesquoleate.

“Antioxidants” include, e.g., butylated hydroxytoluene (BHT),butylhydroxyanisole (BHA), ascorbic acid, sodium ascorbate, andtocopherol. Combinations of one or more antioxidants can also be used.

“Binders” impart cohesive qualities and include, e.g., alginic acid andsalts thereof; cellulose derivatives such as carboxymethylcellulose,methylcellulose (e.g., Methocel®), hydroxypropylmethylcellulose,hydroxyethylcellulose, hydroxypropylcellulose (e.g., Klucel®),ethylcellulose (e.g., Ethocel®), and microcrystalline cellulose (e.g.,Avicel® PH101 and Avicel® PH102); silicified microcrystalline cellulose(ProSolv SMCC®), microcrystalline dextrose; amylose; magnesium aluminumsilicate; polysaccharide acids; bentonites; gelatin;polyvinylpyrrolidone/vinyl acetate copolymer; crosspovidone; povidone;starch, such as corn starch, potato starch, wheat starch, rice starch;pregelatinized starch; tragacanth, dextrin, a sugar, such as sucrose(e.g., Dipac®), glucose, dextrose, molasses, mannitol, sorbitol, xylitol(e.g., Xylitab®), and lactose; a natural or synthetic gum such asacacia, tragacanth, ghatti gum, mucilage of isapol husks, polyvinylalcohol, polyvinylpyrrolidone (e.g., Povidone® CL, Kollidon® CL,Polyplasdone® XL-10), larch arabogalactan, Veegum®, polyethylene glycol,waxes, sodium alginate, and the like. Combinations of one or morebinders can also be used.

“Bioavailability” refers to the degree to which a drug becomes availableat the site(s) of action after administration. By way of illustration,the bioavailability of a ganaxolone formulation refers to the percentageof the weight of ganaxolone dosed that is delivered into the generalcirculation of the animal or human being studied. The total exposure(AUC_((0-∞))) of a drug when administered intravenously is usuallydefined as 100% bioavailable (F %). “Oral bioavailability” refers to theextent to which ganaxolone is absorbed into the general circulation whenthe pharmaceutical composition is taken orally as compared tointravenous injection. The degree and timing in which an active agentbecomes available to the target site(s) after administration isdetermined by many factors, including the dosage form and variousproperties, e.g., solubility and dissolution rate of the drug.

A “blood serum concentration” or “blood plasma concentration” or “serumor plasma concentration or level”, typically measured in mg, μg, or ngof a drug per ml, dl, or 1 of serum or plasma absorbed into thebloodstream after administration. As used herein, measurable plasmaconcentrations are typically measured in ng/ml or μg/ml. It isunderstood that the plasma concentration of a ganaxolone may varysignificantly between subjects, due to variability with respect tometabolism and/or possible interactions with other therapeutic agents.In accordance with one aspect of the present invention, the blood plasmaconcentration of ganaxolone may vary from subject to subject. Likewise,values such as measured concentration of the active agent in the plasmaat the point of maximum concentration (C_(max)) or time to reach maximumplasma concentration (T_(max)), or total area under the plasmaconcentration time curve (AUC_((0-∞))) may vary from subject to subject.

“AUC_((0-τ)) or “exposure” is the area under the curve of a graph of theconcentration of the active agent (typically plasma concentration) vs.time (τ), measured from time 0 to τ. AUC_((0-τ)) is also used to definethe exposure to the drug over a defined period of time. Due tovariability, the amount necessary to constitute “a therapeuticallyeffective amount” of ganaxolone may vary from subject to subject.

“Carrier materials” include any commonly used excipients inpharmaceutics and should be selected on the basis of compatibility withganaxolone and the release profile properties of the desired dosageform. Exemplary carrier materials include, e.g., binders, suspendingagents, disintegration agents, filling agents, surfactants,solubilizers, stabilizers, lubricants, wetting agents, diluents, and thelike. “Pharmaceutically compatible carrier materials” may comprise, butare not limited to, acacia, gelatin, colloidal silicon dioxide, calciumglycerophosphate, calcium lactate, maltodextrin, glycerin, magnesiumsilicate, polyvinylpyrrolidone (PVP), cholesterol, cholesterol esters,sodium caseinate, soy lecithin, taurocholic acid, phosphotidylcholine,sodium chloride, tricalcium phosphate, dipotassium phosphate, celluloseand cellulose conjugates, sugars sodium stearoyl lactylate, carrageenan,monoglyceride, diglyceride, pregelatinized starch, and the like. See,e.g., Remington: The Science and Practice of Pharmacy, Nineteenth Ed(Easton, Pa.: Mack Publishing Company, 1995); Hoover, John E.,Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton, Pa.1975; Liberman, H. A. and Lachman, L., Eds., Pharmaceutical DosageForms, Marcel Decker, New York, N.Y., 1980; and Pharmaceutical DosageForms and Drug Delivery Systems, Seventh Ed. (Lippincott Williams &Wilkins 1999).

“Conventional Ganaxolone Formulations,” as used herein, refers toganaxolone formulations previously administered to subjects. Suchformulations include ganaxolone formulated with β-cyclodextrin or2-hydroxypropyl-β-cyclodextrin. As published data is dominated by theuse of the ganaxolone/β-cyclodextrin 1:1 complex, this formulation isthe preferred standard by which to compare the ganaxolone formulationsdescribed herein.

The term “curing” means a sufficient time until an endpoint is reachedsuch that the D50 does not change or substantially change after time inconsecutive measurements separated by approx. 72 hours, e.g., by morethan the accuracy of the measuring instrument±5%. in 72 hours after thecuring period. Preferred curing times are 1-20 days, 2-15 days or 3-10days.

“Dispersing agents,” and/or “viscosity modulating agents” includematerials that control the diffusion and homogeneity of a drug throughliquid media or a granulation method or blend method. In someembodiments, these agents also facilitate the effectiveness of a coatingor eroding matrix. Exemplary diffusion facilitators/dispersing agentsinclude, e.g., hydrophilic polymers, electrolytes, Tween ® 60 or 80,PEG, polyvinylpyrrolidone (PVP; commercially known as Plasdone®), andthe carbohydrate-based dispersing agents such as cellulosics, forexample, hydroxypropylcelluloses (e.g., HPC, HPC-SL, and HPC-L),hydroxypropylmethylcellulose's (e.g., Pharmacoat 603, HPMC K100, HPMCK4M, HPMC K15M, and HPMC K100M), carboxymethylcellulose sodium,methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose,noncrystalline cellulose, microcrystalline cellulose, silicifiedmicrocrystalline cellulose, hydroxypropylmethylcellulose phthalate, andhydroxypropylmethylcellulose acetate stearate (HPMCAS). Other dispersingagents include magnesium aluminum silicate, triethanolamine, polyvinylalcohol (PVA), vinyl pyrrolidone/vinyl acetate copolymer (S630),4-(1,1,3,3-tetramethylbutyl)-phenol polymer with ethylene oxide andformaldehyde (also known as tyloxapol), poloxamers (e.g., PluronicsF68®, F88®, and F108®, which are block copolymers of ethylene oxide andpropylene oxide); and poloxamines (e.g., Tetronic 908®, also known asPoloxamine 908®, which is a tetrafunctional block copolymer derived fromsequential addition of propylene oxide and ethylene oxide toethylenediamine (BASF Corporation, Parsippany, N.J.)),polyvinylpyrrolidone K12, polyvinylpyrrolidone K17, polyvinylpyrrolidoneK25, or polyvinylpyrrolidone K30, polyvinylpyrrolidone/vinyl acetatecopolymer (S-630), polyethylene glycol, e.g., the polyethylene glycolcan have a molecular weight of about 300 to about 6000, or about 3350 toabout 4000, or about 7000 to about 5400, polysorbate-80, sodiumalginate, gums, such as gum tragacanth and gum acacia, guar gum,xanthans, including xanthan gum, sugars, polysorbate-80, sodiumalginate, polyethoxylated sorbitan monolaurate, polyethoxylated sorbitanmonolaurate, povidone, carbomers, alginates, chitosans and combinationsthereof. Plasticizers such as cellulose or triethyl cellulose can alsobe used as dispersing agents. Dispersing agents particularly useful inliposomal dispersions and self-emulsifying dispersions are dimyristoylphosphatidyl choline, natural phosphatidyl choline from eggs, naturalphosphatidyl glycerol from eggs, cholesterol and isopropyl myristate.

The term “complex” or “ganaxolone complex” indicates an association ofmolecules and/or a particle including ganaxolone and optionally othermolecules which results in better stability of ganaxolone particles orsome other desirable effect. In some cases, complexing agents initiallyincrease particle size (D50) before imparting stability or otherbeneficial attributes to the formulation. In certain embodiments,ganaxolone complexes made by adding complexing agents requires a curingtime.

“Complexing agents” are molecules which when added to a small particlecomposition (D50 of about 75 to about 400 nm) under the appropriateconditions will act as a stabilizing agent. Addition of a complexingagent can also impart additional suspension stability during freeze/thawcycles and boiling if sterilization is needed. Complexing agents includesmall compounds under MW. 550, which do not contain a sulfonic acid orsulfonic acid/inorganic salt counterion group at the end of an alkylchain containing more than one saturated carbon atom bonded to thecarbon atom bearing the sulfonic acid moiety. Complexing agents includebut are not limited to phenols and phenolic salts, aromatic acids andesters, carboxylic acids and salts and esters thereof, inorganic acidsand bases and amino acids and esters and salts thereof. Some examplesinclude but are not limited to phenol, methylparaben, propylparaben,potassium methylparaben, sodium methylparaben, BHT, sorbic acid,ascorbic acid, p-aminobenzoic acid, benzoic acid ascorbic acid, methylanthranilate, anthranilic acid, picolinic acids and alkyl estersthereof, and sodium benzoate. “Controlled Release” or “ModifiedRelease”, consistent with its use herein, means a dosage form for whichthe drug release characteristics versus time and/or conditions at thesite of dissolution are chosen to accomplish therapeutic or convenienceobjectives not offered by conventional immediate release dosage forms.Controlled release dosage forms include sustained release, prolongedrelease, pulsatile release and delayed release forms. Controlled releasedosage forms can provide therapeutically effective levels of drug for anextended period of time and therefore provide a longer therapeuticperiod relative to immediate release forms.

“Delayed Release”, consistent with its use herein, means a dosage formthat releases a drug at any time other than immediately afteradministration and/or at any other location in the gastrointestinaltract more distal to that which would have been accomplished by animmediate release dosage form. Enteric coated dosage forms are anexample of a delayed release dosage form.

“Diluents” increase bulk of the composition to facilitate compression orcreate sufficient bulk for homogenous blend for capsule filling. Suchcompounds include e.g., lactose, starch, mannitol, sorbitol, dextrose,microcrystalline cellulose such as Avicel®; dibasic calcium phosphate,dicalcium phosphate dihydrate; tricalcium phosphate, calcium phosphate;anhydrous lactose, spray-dried lactose; pregelatinized starch,compressible sugar, such as Di-Pac® (Amstar); mannitol,hydroxypropylmethylcellulose, hydroxypropylmethylcellulose acetatestearate, sucrose-based diluents, confectioner's sugar; monobasiccalcium sulfate monohydrate, calcium sulfate dihydrate; calcium lactatetrihydrate, dextrates; hydrolyzed cereal solids, amylose; powderedcellulose, calcium carbonate; glycine, kaolin; mannitol, sodiumchloride; inositol, bentonite, and the like. Combinations of one or morediluents can also be used.

The term “disintegrate” is the dispersion of the dosage form whencontacted with gastrointestinal fluid or a dispersing agent.“Disintegration agents or disintegrants” facilitate the breakup ordisintegration of a formulation. Examples of disintegration agentsinclude a starch, e.g., a natural starch such as corn starch or potatostarch, a pregelatinized starch such as National 1551 or Amijel®, orsodium starch glycolate such as Promogel® or Explotab®, a cellulose suchas a wood product, microcrystalline cellulose, e.g., Avicel®, Avicel®PH101, Avicel® PH102, Avicel® PH105, Elcema® P100, Emcocel®, Vivacel®,Ming Tia®, and Solka-Floc®, methylcellulose, croscarmellose, or across-linked cellulose, such as cross-linked sodiumcarboxymethylcellulose (Ac-Di-Sol®), cross-linkedcarboxymethylcellulose, or cross-linked croscarmellose, a cross-linkedstarch such as sodium starch glycolate, a cross-linked polymer such ascrosspovidone, a cross-linked polyvinylpyrrolidone, alginate such asalginic acid or a salt of alginic acid such as sodium alginate, a claysuch as Veegum® HV (magnesium aluminum silicate), a gum such as agar,guar, locust bean, Karaya, pectin, or tragacanth, sodium starchglycolate (Explotab®), bentonite, a natural sponge, a surfactant, aresin such as a cation-exchange resin, citrus pulp, sodium laurylsulfate, sodium lauryl sulfate in combination starch, and the like.

“Drug absorption” or “absorption” typically refers to the process ofmovement of drug from site of administration of a drug across a barrierinto a blood vessel or the site of action, e.g., a drug moving from thegastrointestinal tract into the portal vein or lymphatic system

“Effective particle size” is interchangeably used with “D50”. By “D50”,it is meant that 50% of the particles are below and 50% of the particlesare above a defined measurement. D50 can be used to describe differentparameters (volume, length, number, area . . . etc). “Effective particlesize” or D50 as used herein indicates the volume-weighted mediandiameter as measured by a laser/light scattering method or equivalent,wherein 50% of the particles, by volume, have a smaller diameter, while50% by volume have a larger diameter. The volume weighted D50 alsorelates to the percentage of weight of the particle under a certainsize. For example a D50 of 500 nm means that 50% of the particulate massis less than 500 nm in diameter and 50% of the particulate mass isgreater than 500 nm in diameter. The effective particle size is measuredby conventional particle size measuring techniques well known to thoseskilled in the art. Such techniques include, for example, sedimentationfield flow fractionation, photon correlation spectroscopy, lightscattering (e.g., with a Microtrac UPA 150), laser diffraction and disccentrifugation. For the purposes of the compositions, formulations andmethods described herein, effective particle size is the volume mediandiameter as determined using laser/light scattering instruments andmethods, e.g. a Horiba LA-910, or Horiba LA-950. Similarly, “D90” is thevolume-weighted diameter, wherein 90% of the particles, by volume, havea smaller diameter, while 10% by volume have a larger diameter and “D10”is the volume-weighted diameter, wherein 10% of the particles, byvolume, have a smaller diameter, while 90% by volume have a largerdiameter. It is sometimes useful to express the D50 value aftersonication for 1 minute or less using about 40 watts of sonicating powerat room temperature (15° C. to 30° C.). This low power and short periodcan break up very loose aggregates which will not typically have anegative impact on the in vivo performance of the composition in asubject.

An “enteric coating” is a substance that remains substantially intact inthe stomach but dissolves and releases the drug in the small intestineand/or colon. Generally, the enteric coating comprises a polymericmaterial that prevents release in the low pH environment of the stomachbut that ionizes or solubilizes at a higher pH, typically a pH of 5 to7, but at least above 3.0, more or above 5, or even more specifically ata pH of about 5.5 to about 7, and thus dissolves sufficiently in thesmall intestine and/or colon to release the active agent therein. Insome embodiments, the enteric coatings release greater than 50% of theganaxolone that is coated in the small intestine. In other embodiments,the enteric coating provides the release of a substantial portion(greater than 40%) of the coated ganaxolone in the mid-small intestine,e.g., the jejunum.

An “enterically coated” formulation of ganaxolone is intended to meanthat some or most of the ganaxolone has been enterically coated toensure that at least some of the drug is released after entering thesmall intestine, rather than the acidic environment of the stomach. Insome embodiments, about 40% to about 60% of the coated ganaxoloneparticles are released in the middle region of the small intestine tominimize interaction with bile acids and minimize food effects. In someembodiments, the enterically coated formulations provide the release ofgreater than 80% of ganaxolone in the small intestine.

The enteric coating material should be non-toxic and is predominantlysoluble in the intestinal fluid, but substantially insoluble in thegastric fluids. Examples include polyvinyl acetate phthalate (PVAP),commercially available under trade names of Opadry® Enteric fromColorcon®, hydroxypropylmethylcellulose acetate succinate (HPMCAS),cellulose acetate phthalate (CAP), methacrylic acid copolymer,hydroxypropylmethylcellulose succinate, cellulose acetate succinate,cellulose acetate hexahydrophthalate, hydroxypropylmethylcellulosehexahydrophthalate, hydroxypropylmethylcellulose phthalate (HPMCP),cellulose propionate phthalate, cellulose acetate maleate, celluloseacetate trimellitate, cellulose acetate butyrate, cellulose acetatepropionate, methacrylic acid/methacrylate polymer, methacrylicacid-methyl methacrylate copolymer, ethylmethacrylate-methylmethacrylate-chlorotrimethylammonium ethylmethacrylate copolymer, and the like, and combinations comprising one ormore of the foregoing enteric polymers. Other examples include naturalresins, such as shellac, SANDARAC, copal collophorium, and combinationscomprising one or more of the foregoing polymers. Yet other examples ofenteric polymers include synthetic resin bearing carboxyl groups. Themethacrylic acid:acrylic acid ethyl ester copolymers are commerciallyavailable under the trade names of “Eudragit® L”, such as Eudragit® L30-D55 from Degussa.

“Erosion facilitators” include materials that control the erosion of aparticular material in gastrointestinal fluid. Erosion facilitators aregenerally known to those of ordinary skill in the art. Exemplary erosionfacilitators include, e.g., hydrophilic polymers, electrolytes,proteins, peptides, and amino acids. Combinations of one or more erosionfacilitator with one or more diffusion facilitator can also be used inthe present invention.

“Filling agents” include compounds such as lactose, calcium carbonate,calcium phosphate, dibasic calcium phosphate, calcium sulfate,microcrystalline cellulose, cellulose powder, dextrose, dextrates,dextran, starches, pregelatinized starch, sucrose, xylitol, lactitol,mannitol, sorbitol, sodium chloride, polyethylene glycol, and the like.

“Flavoring agents” and/or “sweeteners” useful in the ganaxoloneformulations described herein, include both natural and artificialagents e.g., acacia syrup, acesulfame K, alitame, anise, apple,aspartame, banana, Bavarian cream, berry, black currant, butterscotch,calcium citrate, camphor, caramel, cherry, cherry cream, chocolate,cinnamon, bubble gum, citrus, citrus punch, citrus cream, cotton candy,cocoa, cola, cool cherry, cool citrus, cyclamate, cylamate, dextrose,eucalyptus, eugenol, fructose, fruit punch, ginger, glycyrrhetinate,glycyrrhiza (licorice) syrup, grape, grapefruit, honey, isomalt, lemon,lime, lemon cream, monoammonium glyrrhizinate (MagnaSweet®), maltol,mannitol, maple, marshmallow, menthol, mint cream, mixed berry,neohesperidine DC, neotame, orange, pear, peach, peppermint, peppermintcream, Prosweet® Powder, raspberry, root beer, rum, saccharin, safrole,sorbitol, spearmint, spearmint cream, strawberry, strawberry cream,stevia, sucralose, sucrose, sodium saccharin, saccharin, aspartame,acesulfame potassium, mannitol, talin, sylitol, sucralose, sorbitol,Swiss cream, tagatose, tangerine, thaumatin, tutti fruitti, vanilla,walnut, watermelon, wild cherry, wintergreen, xylitol, or anycombination of these flavoring ingredients, e.g., anise-menthol,cherry-anise, cinnamon-orange, cherry-cinnamon, chocolate-mint,honey-lemon, lemon-lime, lemon-mint, menthol-eucalyptus, orange-cream,vanilla-mint, and mixtures thereof.

The term “grinding media” refers to the material used in milling tophysically reduce the particle size of a composition. For millingoperations, preferred grinding media are spherical balls of yttriumstabilized zirconium oxide, glass or a plastic resin.

“Gastrointestinal fluid” is the fluid of the gastrointestinal tract of asubject or the saliva of a subject or the equivalent thereof. An“equivalent” of stomach or gastric secretion” is an in vitro fluidhaving similar content and/or pH as stomach secretions such as simulatedgastric fluid (SGF) prepared using USP guidance of about 0.1N HClsolution in water containing about 0.03M NaCl at a pH of around 1.2. Inaddition, an “equivalent” of intestinal secretion” is an in vitro fluidhaving similar content and/or pH as intestinal secretions such assimulated intestinal fluid (SIF) prepared using USP guidance is anaqueous phosphate buffer system at pH Of 6.7-6.9.

“Ionic Dispersion Modulator” is defined as an organic or inorganicmolecule which when added to a small particle composition will change atleast one of the following: viscosity, the amount of certainingredient(s) needed to stabilize particles during the removal ofsolvent and/or the amount of certain ingredient(s) needed to stabilizesolid dosage forms or blends when re-dispersed in SGF and SIF asdescribed in Example 28. An ionic dispersion modulator does not containa sulfonic acid or sulfonic acid/inorganic salt group at the end of analkyl carbon chain containing at least 1 saturated carbon atom bonded tothe carbon atom bearing the sulfonic acid moiety.

“Immediate Release” means a dosage form that releases at least 80% ofdrug within 2 hours of administration, more specifically, within 1 hourof addition to a commonly accepted simulated gastric fluid. Typically animmediate release composition is tested in dissolution apparatus (typeII most common) in an amount considered to be therapeutic in patientsand a volume of SGF of 500-1000 mL.

“Lubricants” and “glidants” are compounds that prevent, reduce orinhibit adhesion or friction of materials. Exemplary lubricants include,e.g., stearic acid, calcium hydroxide, talc, sodium stearyl fumarate, ahydrocarbon such as mineral oil, or hydrogenated vegetable oil such ashydrogenated soybean oil (Sterotex®), higher fatty acids and theiralkali-metal and alkaline earth metal salts, such as aluminum, calcium,magnesium, zinc, stearic acid, sodium stearates, glycerol, talc, waxes,Stearowet®, boric acid, sodium benzoate, sodium acetate, sodiumchloride, leucine, a polyethylene glycol (e.g., PEG-4000) or amethoxypolyethylene glycol such as Carbowax™, sodium oleate, sodiumbenzoate, glyceryl behenate, polyethylene glycol, magnesium or sodiumlauryl sulfate, colloidal silica such as Syloid™, Cab-O-Sil®, a starchsuch as corn starch, silicone oil, a surfactant, and the like.

“Milling chamber void volume” is the open volume in a milling chamberavailable to the milling slurry after grinding media has been added.Milling chamber void volume is related to the amount of grinding media(volume %) and the volume of open space when the spherical beads arestacked on one another (grinding media void volume). For 0.2-0.4 mmspherical milling grinding media, a range of approx. 36-42% of thevolume occupied by the grinding beads is the grinding media void volume.Milling chamber void volume (mL)=Total milling chamber volume(mL)−volume of grinding media (mL)+grinding media void volume (mL)

“Milling Residence Time” is the time that a particle is present in themilling chamber over the total time of milling to obtain desiredparticles. Milling Residence Time (MRT) is defined as: MRT(minutes)=Milling chamber void volume (ml)×total milling time(minutes.)/Milling Slurry Vol. (ml)

The term “Milling Slurry” refers to a suspension containing the drug forparticle size reduction and other ingredients to facilitate the millingprocess. The composition of the milling slurry is usually not the finalformulation composition

The term “milling media” refers to the components of the milling slurryminus the active pharmaceutical ingredient(s).

The term “Milled Slurry” refers the milling slurry after it had beenreduced to a small particle suspension by milling. The most preferredmilling slurries for a liquid dispersion are those that meet particlesize and compositions that can be diluted with water and appropriateingredients to obtain the final formulation. For a solid dosage form,preferred milled slurries are those that can be utilized with minimalmanipulation to yield the final solid dosage form.

“Pharmacodynamics” refers to the factors which determine the biologicresponse observed relative to the concentration of drug at a site ofaction.

“Particle Size” refers to a measured distribution of particles and isusually expressed as the “volume weighted median” size unless specifiedotherwise. Measurement of particle size for ganaxolone formulationsdescribed herein use a Horiba LA-910 or Horiba LA-950 laser lightscattering instrument with approx. 120 ml of distilled water in thesample chamber, recirculation mode set to 4, agitation set to 1. If theparticle size is measured after sonication, the sonication power is setto “low” (40 watts) and the sonication time is 1 minute. This lowsonication setting and short duration effectively breaks up very looseaggregates that would not typically affect formulation performance. Forganaxolone the relative refractive index setting is set to 115-010 andsample is added to give a tungsten (blue) light transmittance value ofapprox. 75%. When measuring a liquid dispersion of ganaxolone, theparticle size can be measured by adding the liquid composition viaplastic pipette directly to the sample chamber or diluting to approx.0.5 mg of ganaxolone/ml and adding via a plastic pipette to the samplechamber. When measuring a solid composition of ganaxolone where allparticles are water soluble, the solid is dispersed in at least 15 ml ofdistilled water, agitated manually and then added via plastic pipette tothe sample chamber. The solid composition contains water insolubleexcipients, they may be removed by filtration through a 5 micron filter,or in the case where the suspension cannot be filtered, and particlesize can be determined by subtracting the signal from the non-ganaxoloneinsoluble components. This is described in the method section of thisdocument.

“Pharmacokinetics” refers to the factors which determine the attainmentand maintenance of the appropriate concentration of drug at a site ofaction.

“Plasticizers” are compounds used to soften the microencapsulationmaterial, film coatings or pharmaceutical blends for compression to makethem less brittle. Suitable plasticizers include, e.g., polyethyleneglycols such as PEG 300, PEG 400, PEG 600, PEG 1450, PEG 3350, and PEG800, stearic acid, propylene glycol, oleic acid, triethyl cellulose andtriacetin. In some embodiments, plasticizers can also function asdispersing agents or wetting agents.

“Preservatives” are compounds which inhibit microbial growth and aretypically added to dispersions to prevent microbes from growing.Typically amounts of preservatives needed to pass anti-microbialeffectiveness testing as described by USP and EU methodology are used totest appropriate preservative levels. Preservatives include but are notlimited to potassium sorbate, methylparaben, propylparaben, benzoic acidand its salts, other esters of parahydroxybenzoic acid such asbutylparaben, alcohols such as ethyl or benzyl alcohol, phenoliccompounds such as phenol, or quarternary compounds such as benzalkoniumchloride.

A “pulsatile release” dosage form is a dosage form capable of providingmore than one peak blood plasma concentration following a singleadministration. A “pulsatile release” formulation can contain acombination of immediate release, sustained release, and/or delayedrelease formulations in the same dosage form. “Pharmacokineticparameters” are parameters which describe the in vivo characteristics ofthe drug over time, including, for example plasma concentration of thedrug. Pharmacokinetic parameters include C_(max), T_(max), and AUC_(0-τ)(each discussed above).

“Solubilizers” include compounds such as triacetin, triethylcitrate,ethyl oleate, ethyl caprylate, sodium lauryl sulfate, sodium doccusate,vitamin E TPGS, dimethylacetamide, N-methylpyrrolidone,N-hydroxyethylpyrrolidone, polyvinylpyrrolidone, hydroxypropylmethylcellulose, hydroxypropyl cyclodextrins, ethanol, n-butanol, isopropylalcohol, cholesterol, bile salts, polyethylene glycol 200 to 600,glycofurol, transcutol, propylene glycol, and dimethyl isosorbide,miglyol, glycerin, glycerol, and the like.

“Spray Drying” is a process by which a solvent is removed from acomposition yielding a dried form of the ingredients in thatcomposition. Drying is effected by spraying the composition through anozzle into a heated environment containing a vacuum or a flow of air orinert gas. Spray drying can produce amorphous powders of drugs orgranulations, both which can be converted into a solid dosage form bythose skilled in the art.

“Spray Layering” is a procedure where a solution or suspensioncontaining ingredients are sprayed through a nozzle into a fluidized bedcontaining particles which are coated with a film containing thecomposition of the solution or suspension as the solvent is removed bythe flow of a heated gas. Spray layering typically involves coating aninert core usually comprised of a sugars and starch or cellulosics orcombinations thereof. Such cores are typically 20 to 35 mesh in size.Spray Layering is used extensively for applying coatings (finish orenteric) to solid dosage formulations as well as spherical beadscontaining a drug for use in a capsule or tablet formulation.

“Stable” means the D50 does not substantially change (greater than 50%)after an initial time is defined (e.g., after milling or a curing period(1 to 3 weeks)) and up to 4 months storage at room temperature (15° to25° C.). For example, the stable ganaxolone particles described hereinin an aqueous dosage form will not show an increase in effectiveparticle size of greater than 50% over a four month storage period, andpreferably no increase in effective particle size of greater than 50%over a two year storage period. Similarly, the stable ganaxoloneparticles described herein in a solid oral dosage form will not show anincrease in effective particle size of greater than 50% up to 4 monthsstorage at room temperature (15° to 25° C.) upon dispersion (methods fordispersion are described in the Examples section below). In someembodiments, the formulations described herein will not produceunidentified ganaxolone degradation impurities up to 4 months storage atroom temperature (15° to 25° C.) at individual levels of about greaterthan 0.1% by weight as compared to the impurity levels at the initialtime designation.

“Stabilizers” include agents which maintain a desirable attribute of theformulation over a time interval including but not limited tomechanical, chemical and temperature stressing that can be tested in alaboratory setting. Such attributes include stable particle size orhomogeneity resulting in concentrations consistent with the labeledpotency and maintaining purity. Some but not all of the attributes arelisted above.

“Steady state,” as used herein, is when the amount of drug administeredis equal to the amount of drug eliminated within one dosing intervalresulting in a plateau or constant plasma drug exposure.

“Subject” as used herein is any mammal. Subjects include individuals inneed of ganaxolone treatment (patients) and individuals not in need ofganaxolone treatment (e.g. normal healthy volunteers. Humans arepreferred subjects and patients.

“Suspending agents” or “dispersing agents” include compounds such aspolyvinylpyrrolidone, e.g., polyvinylpyrrolidone K12,polyvinylpyrrolidone K17, polyvinylpyrrolidone K25, orpolyvinylpyrrolidone K30, vinyl pyrrolidone/vinyl acetate copolymer(S630), polyethylene glycol, e.g., the polyethylene glycol can have amolecular weight of about 300 to about 6000, or about 3350 to about4000, or about 7000 to about 5400, sodium carboxymethylcellulose,methylcellulose, hydroxypropylcelluloses (e.g., HPC, HPC-SL, and HPC-L),cellulosics, such as, e.g., sodium carboxymethylcellulose,methylcellulose, sodium carboxymethylcellulosehydroxypropylmethylcellulose (e.g., HPMC 2910, Pharmacoat 603, HPMCK100, HPMC K4M, HPMC K15M, and HPMC K100M), hydroxyethylcellulosehydroxymethylcellulose acetate stearate, polysorbate-80,hydroxyethylcellulose, sodium alginate, gums, such as, e.g., gumtragacanth and gum acacia, guar gum, xanthans, including xanthan gum,sugars, polyethoxylated sorbitan monolaurate, polyethoxylated sorbitanmonolaurate, povidone, magnesium aluminum silicate,4-(1,1,3,3-tetramethylbutyl)-phenol polymer with ethylene oxide andformaldehyde (also known as tyloxapol), poloxamers, pluronics, and thelike. Combinations of HPMC and PVA are especially useful.

“Sustained Release”, consistent with its use herein, means a dosage formthat allows at least a one dose reduction in dosing frequency per day ascompared to the drug in conventional form, such as a solution or animmediate release solid dosage form.

“Surfactants” include compounds such as sodium lauryl sulfate, sodiumdoccusate, triacetin, vitamin E TPGS, dioctylsulfosuccinate, gelatin,casein, lecithin (phosphatides), dextran, gum acacia, cholesterol,tragacanth, stearic acid, benzalkonium chloride, calcium stearate,glycerol monostearate, cetostearyl alcohol, cetomacrogol emulsifyingwax, sorbitan esters, polyoxyethylene alkyl ethers (e.g., macrogolethers such as cetomacrogol 1000), polyoxyethylene castor oilderivatives, polyoxyethylene sorbitan fatty acid esters (e.g., thecommercially available Tweens® such as e.g., Tween 20® and Tween 80®(ICI Speciality Chemicals)); polyethylene glycols (e.g., Carbowaxs 3550®and 934® (Union Carbide)), polyoxyethylene stearates, colloidal silicondioxide, phosphates, carboxymethylcellulose calcium,carboxymethylcellulose sodium, methylcellulose, hydroxyethylcellulose,hydroxypropyl methylcellulose, hydroxypropylcellulose,polyvinylpyrrolidone, hydroxypropylmethylcellulose phthalate,noncrystalline cellulose, magnesium aluminium silicate, triethanolamine,polyvinyl alcohol (PVA), 4-(1,1,3,3-tetramethylbutyl)-phenol polymerwith ethylene oxide and formaldehyde (also known as tyloxapol,superione, and triton), poloxamers (e.g., Pluronics F68® and F108®,which are block copolymers of ethylene oxide and propylene oxide);poloxamines (e.g., Tetronic 908®, also known as Poloxamine 9085®, whichis a tetrafunctional block copolymer derived from sequential addition ofpropylene oxide and ethylene oxide to ethylenediamine (BASF WyandotteCorporation, Parsippany, N.J.)); Tetronic 1508® (T-1508, a poloxamine)(BASF Wyandotte Corporation), Tritons X-200®, which is an alkyl arylpolyether sulfonate (Rohm and Haas); Crodestas F-1106, which is amixture of sucrose stearate and sucrose distearate (Croda Inc.);p-isononylphenoxypoly-(glycidol), also known as Olin-IOG® or Surfactant10-G® (Olin Chemicals, Stamford, Conn.); Crodestas SL-40® (Croda, Inc.);and SA90HCO, which is C₁₈H₃₇CH₂C(O)N(CH₃)—CH₂(CHOH)₄(CH₂OH)₂ (EastmanKodak Co.); decanoyl-N-methylglucamide; n-decyl β-D-glucopyranoside;n-decyl β-D-maltopyranoside; n-dodecyl β-D-glucopyranoside; n-dodecylβ-D-maltoside; heptanoyl-N-methylglucamide;n-heptyl-β-D-glucopyranoside; n-heptyl β-D-thioglucoside; n-hexylβ-D-glucopyranoside; nonanoyl-N-methylglucamide; n-noylβ-D-glucopyranoside; octanoyl-N-methylglucamide;n-octyl-β-D-glucopyranoside; octyl β-D-thioglucopyranoside;PEG-phospholipid, PEG-cholesterol, PEG-cholesterol derivative,PEG-vitamin A, PEG-vitamin E, lysozyme, random copolymers of vinylpyrrolidone and vinyl acetate. The above surfactants are commerciallyavailable or can be prepared by techniques known in the art. Many aredescribed in detail in the Handbook of Pharmaceutical Excipients,published jointly by the American Pharmaceutical Association and ThePharmaceutical Society of Great Britain (The Pharmaceutical Press,2000), specifically incorporated by reference.

A “therapeutically effective amount” or “effective amount” is thatamount of a pharmaceutical agent to achieve a pharmacological effect.The term “therapeutically effective amount” includes, for example, aprophylactically effective amount. An “effective amount” of ganaxoloneis an amount needed to achieve a desired pharmacologic effect ortherapeutic improvement without undue adverse side effects. Theeffective amount of a ganaxolone will be selected by those skilled inthe art depending on the particular patient and the disease. It isunderstood that “an effect amount” or “a therapeutically effectiveamount” can vary from subject to subject, due to variation in metabolismof ganaxolone, age, weight, general condition of the subject, thecondition being treated, the severity of the condition being treated,and the judgment of the prescribing physician.

“Treat” or “treatment” refers to any treatment of a disorder or disease,such as preventing the disorder or disease from occurring in a subjectwhich may be predisposed to the disorder or disease, but has not yetbeen diagnosed as having the disorder or disease; inhibiting thedisorder or disease, e.g., arresting the development of the disorder ordisease, relieving the disorder or disease, causing regression of thedisorder or disease, relieving a condition caused by the disease ordisorder, or reducing the symptoms of the disease or disorder.

“Viscosity enhancing agents” are agents which are typically added to aparticulate dispersion to increase the viscosity and prevent or slowsettling of the particles. Viscosity enhancing agents in solid dosageforms are used on occasion to form a gel matrix as water permeates thesolid dosage form and can delay the release of the pharmaceuticallyactive ingredient(s). Viscosity enhancing agents include but are notlimited to the following: methyl cellulose, xanthangum,carboxymethylcellulose, hydroxypropylcellulose,hydroxypropylmethylcellulose,hydroxypropylmethylcelluloseacetatestearate,hydroxypropylmethylcellulose phthalate, carbomer, polyvinyl alcohol,alginates, acacia, chitosans and combinations thereof.

“Wetting agents” include surfactants and are used to enhance thedispersion of a drug in a composition or after administration of thecomposition to a subject. Wetting agents can also act as stabilizers.Examples of wetting agents include compounds such as oleic acid,glyceryl monostearate, sorbitan monooleate, sorbitan monolaurate,triethanolamine oleate, polyoxyethylene sorbitan monooleate,polyoxyethylene sorbitan monolaurate, sodium docusate, sodium oleate,sodium lauryl sulfate, sodium doccusate, triacetin, Tween 80, vitamin ETPGS, ammonium salts and the like.

I. Ganaxolone Formulations and Compositions

Ganaxolone is poorly soluble in water and other pharmaceuticallyacceptable solvents. As a result of its low aqueous solubility, thereexists a need in the art for ganaxolone formulations, which provideincreased bioavailability and therapeutic efficacy of ganaxolone.However, it is known that increasing the bioavailability of an activeagent likewise results in the possibility of increased side effects.

Certain ganaxolone compositions and formulations described hereindisplay enhanced pharmacokinetic (PK) and pharmacodynamic (PD) profilesand/or minimized side effects as compared to conventional ganaxoloneformulations known in the art. Specifically, certain ganaxoloneformulations described herein provide increased therapeutic benefitresulting from enhanced PK/PD properties including increased exposure ofganaxolone in the fasted or fed state, improved maintenance ofganaxolone at steady state, and decreased maximal plasma levels(C_(max)) of ganaxolone as compared to the levels immediately prior tothe next dose (C_(min)) at steady state. Certain ganaxolone compositionsand formulations described herein also provide a reduced fed/fastedexposure and/or C_(max) ratio with the administration of ganaxolone,extended periods of ganaxolone exposure per dose, reduced plasma C_(max)levels needed to achieve efficacious exposure over a dosing interval atsteady state, steady state plasma levels immediately prior to the nextdose of about 20 to 50 ng/ml and a C_(max)/C_(min) ratio less than 4 inan aqueous oral composition and a C_(max)/C_(min), ratio less than 3 ina solid dosage form for oral administration at steady state. Steadystate plasma levels of certain ganaxolone formulations described hereinare about 50 ng/ml or from about 100 ng/ml to about 10 ng/ml.

Certain formulations described herein reduce the risk of ganaxolone sideeffects including ataxia, sedation and somnolence relative toconventional ganaxolone formulations. In certain embodiments improvedperformance compared to conventional ganaxolone formulations can be seenon acute doses. In other embodiments, maximal benefit of the ganaxoloneformulations described herein can be seen at steady state.

The ganaxolone formulations described herein can be administered to asubject by conventional administration route. Ganaxolone oral soliddosage forms and oral aqueous suspensions are included herein. Modified,controlled, and pulsatile release ganaxolone dosages forms are providedherein.

It is to be understood that any of the dosage forms described hereincomprising a ganaxolone formulation, either alone or when administeredin combination with another drug can provide at least one or more of theabove-described enhanced pharmacokinetic properties and minimize sideeffects resulting from reduced T_(max) and elevated C_(max) levels ofganaxolone in the blood plasma.

II. Ganaxolone Particles

The ganaxolone formulations described herein comprise stable ganaxoloneparticles existing in crystalline form, amorphous form, semi-crystallineform, semi-amorphous form, and mixtures thereof. In some embodiments,the ganaxolone formulations comprise an amorphous form of ganaxolonehaving an average effective particle size of up to about 10 microns. Inother embodiments, the ganaxolone formulations comprise an amorphousform of ganaxolone, which is either coated or encapsulated with anexcipient matrix, with the matrix having an effective particle size upto 300 microns. In other embodiments, the ganaxolone formulationscomprise a non-amorphous form of ganaxolone comprising ganaxoloneparticles having an effective average particle size by weight of lessthan about 500 nm. In other embodiments, the ganaxolone particles havean effective average particle size by weight of less than about 400 nm,an effective average particle size by weight of less than about 300 nm,an effective average particle size by weight of less than about 200 nm,or an average effective particle size by weight of less than about 100nm when measured by the above techniques. In yet another embodiment, theganaxolone particles have a particle size distribution wherein theganaxolone particles have an effective particle size by weight of lessthan about 400 nm and wherein the standard deviation of the particlesize distribution is less than about 100 nm.

In other embodiments, the ganaxolone particles by weight have a particlesize 500 nm, i.e., less than about 500 nm, less than about 400 nm, lessthan about 300 nm, less than about 200 nm, or less than about 100 nmwith less than at least 20%, at least about 15% or at least about 10% ofthe total particles having a particle size greater than 1 micron.

In one embodiment, the ganaxolone particles have a particle size ofaround 300 nm with a distribution wherein 90% of the particles by weighthave an effective particle size by weight between about 100 nm and 800nm. In another embodiment, the ganaxolone particles have a particle sizeor around 100 nm and a distribution wherein 90% of the particles byweight have an effective particle size by weight between about 50 nm and250 nm.

In other embodiments, the ganaxolone compositions described hereincomprise stable ganaxolone particles having a particle size by weight ofless than 500 nm formulated with ganaxolone particles having a particlesize by weight of greater than 500 nm. In such embodiments, theformulations have a particle size distribution wherein about 10% toabout 100% of the ganaxolone particles by weight are between about 100nm and about 300 nm, about 0% to about 90% of the ganaxolone particlesby weight are between about 300 nm and about 600 nm, and about 0% toabout 30% of the ganaxolone particles by weight are greater than about600 nm. In one embodiment, the formulation has a particle sizedistribution wherein about 20% of the ganaxolone particles by weight arebetween about 100 nm and about 300 nm, about 40% of the ganaxoloneparticles by weight are between about 300 nm and about 600 nm, and about30% of the ganaxolone particles by weight are greater than about 600 nm.In still another embodiment, the formulation has a particle sizedistribution wherein about 30% of the ganaxolone particles by weight arebetween about 100 nm and about 300 nm, about 40% of the ganaxoloneparticles by weight are between about 300 nm and about 600 nm, and about30% of the ganaxolone particles by weight are greater than about 600 nm.In yet another embodiment, the formulation has a particle sizedistribution wherein about 50% of the ganaxolone particles by weight arebetween about 100 nm and about 300 nm, about 40% of the ganaxoloneparticles by weight are between about 300 nm and about 800 nm, and about10% of the ganaxolone particles by weight are greater than about 800 nm.

III. Benefits of Small Particle Sizes of Poorly Soluble Drugs

The particle size of ganaxolone particles is an important factor whichcan effect bioavailability, blend uniformity, segregation, and flowproperties. In general, smaller particle sizes of a drug increases thedrug absorption rate of permeable drugs with substantially poor watersolubility by increasing the surface area and kinetic dissolution rate.The particle size of ganaxolone can also affect the suspension or blendproperties of the pharmaceutical formulation. For example, smallerparticles are less likely to settle and therefore form bettersuspensions.

In various embodiments, the ganaxolone formulations, in aqueousdispersions or as dry powders (which can be administered directly, as apowder for suspension, or used in a solid dosage form), can comprise anon-amorphous form of ganaxolone with compatible excipients having aneffective particle size by weight of less than about 500 nm, or lessthan about 400 nm, or less than about 300 nm, or less than about 200 nm,or less than about 100 nm. In other embodiments, the ganaxoloneformulations comprise an amorphous form of ganaxolone with compatibleexcipients having an average effective particle size by weight of up toabout 10 microns.

Effects of Particle Size Range of Poorly Soluble Drugs

The amount of a permeable water insoluble drug (<1 mg/ml in water at pH7) that can be absorbed is related to its particle size. In variousembodiments, stable ganaxolone particles can be obtained with a D50 ofless than about 100-500 nm. As one reduces particles further, thekinetic dissolution rate increases as a function of the drugs surfacearea. In general, reducing the drugs particle size in half doubles thesurface area of the particles. When poorly soluble drugs (<1 mg/ml watersolubility at pH 7 to 7.4) are extensively milled (long millingresidence time), small particles of around 100 nm can be obtained. Theseparticles tend to have a mean value within 25 to 30% of the median, astandard deviation of less than around 50% of the D50 value and a D90 ofaround 1.5 to 1.75 times the D50 value. Very small particles (50 to 200nm) with a tight distribution around the D50 value as described abovecan result in high maximal plasma levels, but occasionally lower totalexposures (AUC_(0-τ)) can be realized as the extended release due toparticle dissolution is lost.

In some instances it is desirable to not have a high Cmax typicallyassociated with small particle formulations. For compounds with high invivo clearance, it is also desirable to extend the absorption phase tominimize the frequency with which dosing in a subject is needed. Oneaspect of this invention is that the ganaxolone complexes formed afteradding a complexing agent and any resulting aggregates can accomplishthis goal in that the surface area of aggregates is typically muchgreater than a single particle of that size. Also in the case ofdispersion of dosage forms in gastrointestinal fluids (simulated or invivo administration), loose aggregates that can dissociate substantiallyduring gastrointestinal transit can provide an extended drug absorptionphase which is desirable. For each compound one has to determine theeffect of these loose and tight aggregates, but it is typical that looseaggregates which can be reversed quickly with a small amount of energy(40 watts of sonication in water for 1 minute or less) will not impactthe performance of the drug exposure and can extend the duration of drugrelease and minimize the plasma C_(max) levels in a subject. For acomposition containing stable ganaxolone particles, it is desirable tohave a D50 with or without sonication between 100 to 500 nm and no morethan about 15% of the ganaxolone particles greater than 1 micron insize.

It is sometimes desirable to obtain a broader distribution of stableparticles than those obtained by milling alone to optimize both themaximal levels and total exposure obtained after a dose of drug. Invarious embodiments, ganaxolone formulations (both liquid and solid)have had a complexing agent added which serves not only to stabilizeparticle growth, but provides a broader range of particles to increasethe exposure to ganaxolone at a given dose. This extended particle sizerange is especially desirable in compounds that had the characteristicof being metabolized extensively by the liver after oral administration.In one embodiment, a ganaxolone dispersion has a particle size of around300 nm, a mean of around 800 nm, a D90 of around 600 nm, a standarddeviation of around 1.8 microns and around 7 to 8% of the particlesgreater than 1 micron.

IV. Dosage Forms

The ganaxolone compositions described herein can be formulated foradministration to a subject via any conventional means including, butnot limited to, oral, parenteral (e.g., intravenous, subcutaneous, orintramuscular), buccal, intranasal or transdermal administration routes.

Moreover, the pharmaceutical ganaxolone compositions described hereincan be formulated into any suitable dosage form, including but notlimited to, aqueous oral dispersions, aqueous oral suspensions, soliddosage forms including oral solid dosage forms, aerosols, controlledrelease formulations, fast melt formulations, effervescent formulations,self-emulsifying dispersions, solid solutions, liposomal dispersions,lyophilized formulations, tablets, capsules, pills, powders, delayedrelease formulations, immediate release formulations, modified releaseformulations, extended release formulations, pulsatile releaseformulations, multiparticulate formulations, and mixed immediate releaseand controlled release formulations. In some embodiments, ganaxoloneformulations provide a therapeutically effective amount of ganaxoloneover an interval of about 30 minutes to about 8 hours afteradministration, enabling, for example, once-a-day, twice-a-day (b.i.d.),or three times a day (t.i.d.) administration if desired. In oneembodiment, the ganaxolone particles are formulated into a controlledrelease or pulsatile solid dosage form for b.i.d. administration. Inother embodiments, the ganaxolone particles are dispersed in an aqueousdispersion for b.i.d. administration. Generally speaking, one willdesire to administer an amount of ganaxolone that is effective toachieve a plasma level commensurate with the concentrations found to beeffective in vivo (e.g., 50 to 100 ng/ml at steady state) for a periodof time effective to elicit a therapeutic effect.

Dosage Forms Characterized by Disintegration Profiles

The various release dosage formulations discussed above can becharacterized by their disintegration profile. A profile ischaracterized by the test conditions selected. Thus the disintegrationprofile can be generated at a pre-selected apparatus type, shaft speed,temperature, volume, and pH of the dispersion media.

Several disintegration profiles can be obtained. For example, a firstdisintegration profile can be measured at a pH level approximating thatof the stomach (about pH 1.2); a second disintegration profile can bemeasured at a pH level approximating that of one point in the intestineor several pH levels approximating multiple points in the intestine(about 6.0 to about 7.5, more specifically, about 6.5 to 7.0). Anotherdisintegration profile can be measured using distilled water.

The release of formulations may also be characterized by theirpharmacokinetic parameters, for example, C_(max), T_(max), andAUC_((0-τ)).

As one embodiment the invention provides an solid oral dosage form thatis a controlled release or pulsatile release dosage form whereby 30 to60% of the ganaxolone particles by weight are released from the dosageform within about 2 hours after administration and about 90% by weightof the ganaxolone particles are released from the dosage form withinabout 7 hours after administration. In another embodiment, a broad sizedistribution of ganaxolone particles by weight are dispersed in anaqueous dispersion comprising ganaxolone particles of varying effectiveparticle sizes such that the smaller particles provide quick absorptionof ganaxolone and the larger particles provide a delayed absorption ofganaxolone. In another embodiment, the solid dosage form is an immediaterelease dosage form whereby >80% of the ganaxolone particles hours afteradministration.

Oral Solid Dosage Forms

In some embodiments, the solid dosage forms of the present invention maybe in the form of a tablet, (including a suspension tablet, a fast-melttablet, a bite-disintegration tablet, a rapid-disintegration tablet, aneffervescent tablet, or a caplet), a pill, a powder (including a sterilepackaged powder, a dispensable powder, or an effervescent powder), acapsule (including both soft or hard capsules, e.g., capsules made fromanimal-derived gelatin or plant-derived HPMC, or “sprinkle capsules”),solid dispersion, solid solution, bioerodible dosage form, controlledrelease formulations, pulsatile release dosage forms, multiparticulatedosage forms, pellets, granules, or an aerosol. In other embodiments,the pharmaceutical formulation is in the form of a powder. In stillother embodiments, the pharmaceutical formulation is in the form of atablet, including but not limited to, a fast-melt tablet. Additionally,pharmaceutical formulations of the present invention may be administeredas a single capsule or in multiple capsule dosage form. In someembodiments, the pharmaceutical formulation is administered in two, orthree, or four, capsules or tablets.

In some embodiments, solid dosage forms, e.g., tablets, effervescenttablets, and capsules, are prepared by mixing ganaxolone particles withone or more pharmaceutical excipients to form a bulk blend composition.When referring to these bulk blend compositions as homogeneous, it ismeant that the ganaxolone particles are dispersed evenly throughout thecomposition so that the composition may be readily subdivided intoequally effective unit dosage forms, such as tablets, pills, andcapsules. The individual unit dosages may also comprise film coatings,which disintegrate upon oral ingestion or upon contact with diluents.These ganaxolone formulations can be manufactured by conventionalpharmaceutical techniques.

Preparation of Solid Dosage Forms

Conventional pharmaceutical techniques for preparation of solid dosageforms include, e.g., one or a combination of methods: (1) dry mixing,(2) direct compression, (3) milling, (4) dry or non-aqueous granulation,(5) wet granulation, or (6) fusion. See, e.g., Lachman et al., TheTheory and Practice of Industrial Pharmacy (1986). Other methodsinclude, e.g., spray drying, pan coating, melt granulation, granulation,fluidized bed spray drying or coating (e.g., wurster coating),tangential coating, top spraying, tableting, extruding and the like.

Formulation Components

The pharmaceutical solid dosage forms described herein can comprise theganaxolone compositions described herein and one or morepharmaceutically acceptable additives such as a compatible carrier,binder, complexing agent, ionic dispersion modulator, filling agent,suspending agent, flavoring agent, sweetening agent, disintegratingagent, dispersing agent, surfactant, lubricant, colorant, diluent,solubilizer, moistening agent, plasticizer, stabilizer, penetrationenhancer, wetting agent, anti-foaming agent, antioxidant, preservative,or one or more combination thereof. In still other aspects, usingstandard coating procedures, such as those described in Remington'sPharmaceutical Sciences, 20th Edition (2000), a film coating is providedaround the ganaxolone formulation. In one embodiment, some or all of theganaxolone particles are coated. In another embodiment, some or all ofthe ganaxolone particles are microencapsulated. In yet anotherembodiment, some or all of the ganaxolone is amorphous material coatedand/or microencapsulated with inert excipients. In still anotherembodiment, the ganaxolone particles not microencapsulated and areuncoated.

Suitable carriers for use in the solid dosage forms described hereininclude, but are not limited to, acacia, gelatin, colloidal silicondioxide, calcium glycerophosphate, calcium lactate, maltodextrin,glycerin, magnesium silicate, sodium caseinate, soy lecithin, sodiumchloride, tricalcium phosphate, dipotassium phosphate, sodium stearoyllactylate, carrageenan, monoglyceride, diglyceride, pregelatinizedstarch, hydroxypropylmethylcellulose, hydroxypropylmethylcelluloseacetate stearate, sucrose, microcrystalline cellulose, lactose, mannitoland the like.

Suitable filling agents for use in the solid dosage forms describedherein include, but are not limited to, lactose, calcium carbonate,calcium phosphate, dibasic calcium phosphate, calcium sulfate,microcrystalline cellulose (e.g., Avicel®, Avicel® PH101, Avicel® PH102,Avicel® PH105, etc.), cellulose powder, dextrose, dextrates, dextran,starches, pregelatinized starch, hydroxypropylmethylcellulose (HPMC),hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcelluloseacetate stearate (HPMCAS), sucrose, xylitol, lactitol, mannitol,sorbitol, sodium chloride, polyethylene glycol, and the like.

Because ganaxolone is insoluble in water and is relatively permeable, itexhibits a strong correlation between the rate of dissolution andbioavailability. Thus, it is important to optimize the rate ofdissolution in biological matrices in order to enhance in vivo drugabsorption. In order to release the ganaxolone from a solid dosage formmatrix as efficiently as possible, disintegrants are often used in theformulation, especially when the dosage forms are compressed withbinder. Disintegrants help rupturing the dosage form matrix by swellingor capillary action when moisture is absorbed into the dosage form. Insome embodiments of the invention, the solid dosage ganaxoloneformulation has greater than about 1 w % of a disintegrant. In variousembodiments of the present invention, the solid dose ganaxoloneformulations have between about 1 w % to about 11 w % or between about 2wt % to about 8 wt % disintegrant. In yet other embodiments, theganaxolone formulations have greater than about 2 wt % disintegrant. Insome embodiments, combinations of disintegrants provide superiordispersion characteristics compared to single disintegrant at a similartotal weight percentage.

Suitable disintegrants for use in the solid dosage forms describedherein include, but are not limited to, natural starch such as cornstarch or potato starch, a pregelatinized starch such as National 1551or Amijel®, or a sodium starch glycolate such as Promogel® or Explotab®,a cellulose such as a wood product, microcrystalline cellulose, e.g.,Avicel®, Avicel® PH101, Avicel® PH102, Avicel® PH105, Elcema® P100,Emcocel®, Vivacel®, Ming Tia®, and Solka-Floc®, methylcellulose,croscarmellose, or a cross-linked cellulose, such as cross-linked sodiumcarboxymethylcellulose (Ac-Di-Sol®), cross-linkedcarboxymethylcellulose, or cross-linked croscarmellose, a cross-linkedstarch such as sodium starch glycolate, a cross-linked polymer such ascrosspovidone, a cross-linked polyvinylpyrrolidone, alginate such asalginic acid or a salt of alginic acid such as sodium alginate, a claysuch as Veegum® HV (magnesium aluminum silicate), a gum such as agar,guar, locust bean, Karaya, pectin, or tragacanth, sodium starchglycolate, bentonite, a natural sponge, a surfactant, a resin such as acation-exchange resin, citrus pulp, sodium lauryl sulfate, sodium laurylsulfate in combination starch, and the like.

In one embodiment, Ac-Di-Sol is the disintegrant. The amount ofAc-Di-Sol used in direct compression tableting may vary with typicalusage levels between 1 and 3 percent. When added to granulations,generally the same percent is used as with a direct compressionformulation. It is often added to both the wet and dried granulationsand blends. The amount of Ac-Di-Sol used in capsule formulationsgenerally ranges from 3-6 percent. Reduced interparticle contact withina capsule facilitates the need for elevated levels of disintegrant.Capsules filled on automatic dosater types of equipment, as opposed tosemi-automatic or hand-filled machines, are more dense and have a harderstructure due to the greater compressional forces needed to form theplug and successfully transfer it into the gelatin or HPMC shell.Greater plug hardness results in greater effectiveness of Ac-Di-Sol.

Binders impart cohesiveness to solid oral dosage form formulations: forpowder filled capsule formulation, they aid in plug formation that canbe filled into soft or hard shell capsules and in tablet formulation,binders ensure that the tablet remains intact after compression and helpassure blend uniformity prior to a compression or fill step. Materialssuitable for use as binders in the solid dosage forms described hereininclude, but are not limited to, carboxymethylcellulose, methylcellulose(e.g., Methocel®), hydroxypropylmethylcellulose (e.g. Hypromellose USPPharmacoat-603, hydroxypropylmethylcellulose acetate stearate (AqoateHS-LF and HS), hydroxyethylcellulose, hydroxypropylcellulose (e.g.,Klucel®), ethylcellulose (e.g., Ethocel®), and microcrystallinecellulose (e.g., Avicel®), microcrystalline dextrose, amylose, magnesiumaluminum silicate, polysaccharide acids, bentonites, gelatin,polyvinylpyrrolidone/vinyl acetate copolymer, crosspovidone, povidone,starch, pregelatinized starch, tragacanth, dextrin, a sugar, such assucrose (e.g., Dipac®), glucose, dextrose, molasses, mannitol, sorbitol,xylitol (e.g., Xylitab®), lactose, a natural or synthetic gum such asacacia, tragacanth, ghatti gum, mucilage of isapol husks, starch,polyvinylpyrrolidone (e.g., Povidone® CL, Kollidon® CL, Polyplasdone®XL-10, and Povidone® K-12), larch arabogalactan, Veegum®, polyethyleneglycol, waxes, sodium alginate, and the like.

In general, binder levels of 20-70% are used in powder-filled gelatincapsule formulations. Binder usage level in tablet formulations is afunction of whether direct compression, wet granulation, rollercompaction, or usage of other excipients such as fillers which itselfcan act as moderate binder are used. Formulators skilled in art candetermine the binder level for the formulations, but binder usage levelof up to 70% in tablet formulations is common.

Suitable lubricants or glidants for use in the solid dosage formsdescribed herein include, but are not limited to, stearic acid, calciumhydroxide, talc, corn starch, sodium stearyl fumarate, alkali-metal andalkaline earth metal salts, such as aluminum, calcium, magnesium, zinc,stearic acid, sodium stearates, magnesium stearate, zinc stearate,waxes, Stearowet®, boric acid, sodium benzoate, sodium acetate, sodiumchloride, leucine, a polyethylene glycol or a methoxypolyethylene glycolsuch as Carbowax™, PEG 4000, PEG 5000, PEG 6000, propylene glycol,sodium oleate, glyceryl behenate, glyceryl palmitostearate, glycerylbenzoate, magnesium or sodium lauryl sulfate, and the like.

Suitable diluents for use in the solid dosage forms described hereininclude, but are not limited to, sugars (including lactose, sucrose, anddextrose), polysaccharides (including dextrates and maltodextrin),polyols (including mannitol, xylitol, and sorbitol), cyclodextrins andthe like.

Non water-soluble diluents are compounds typically used in theformulation of pharmaceuticals, such as calcium phosphate, calciumsulfate, starches, modified starches and microcrystalline cellulose, andmicrocellulose (e.g., having a density of about 0.45 g/cm³, e.g. Avicel,powdered cellulose), and talc.

Suitable wetting agents for use in the solid dosage forms describedherein include, for example, oleic acid, glyceryl monostearate, sorbitanmonooleate, sorbitan monolaurate, triethanolamine oleate,polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitanmonolaurate, quaternary ammonium compounds (e.g., Polyquat 10®), sodiumoleate, sodium lauryl sulfate, magnesium stearate, sodium docusate,triacetin, vitamin E TPGS and the like. Wetting agents includesurfactants.

Suitable surfactants for use in the solid dosage forms described hereininclude, for example, docusate and its pharmaceutically acceptablesalts, sodium lauryl sulfate, sorbitan monooleate, polyoxyethylenesorbitan monooleate, polysorbates, polaxomers, bile salts, glycerylmonostearate, copolymers of ethylene oxide and propylene oxide, e.g.,Pluronic® (BASF), and the like.

Suitable suspending agents for use in the solid dosage forms describedhere include, but are not limited to, polyvinylpyrrolidone, e.g.,polyvinylpyrrolidone K12, polyvinylpyrrolidone K17, polyvinylpyrrolidoneK25, or polyvinylpyrrolidone K30, polyethylene glycol, e.g., thepolyethylene glycol can have a molecular weight of about 300 to about6000, or about 3350 to about 4000, or about 7000 to about 18000, vinylpyrrolidone/vinyl acetate copolymer (S630), sodium alginate, gums, suchas, e.g., gum tragacanth and gum acacia, guar gum, xanthans, includingxanthan gum, sugars, cellulosics, such as, e.g., sodiumcarboxymethylcellulose, methylcellulose, sodium carboxymethylcellulose,hydroxypropylmethylcellulose, hydroxyethylcellulose, polysorbate-80,polyethoxylated sorbitan monolaurate, polyethoxylated sorbitanmonolaurate, povidone and the like.

Suitable antioxidants for use in the solid dosage forms described hereininclude, for example, e.g., butylated hydroxytoluene (BHT),butylhydroxyanisole (BHA), sodium ascorbate, Vitamin E TPGS, ascorbicacid, sorbic acid and tocopherol.

It should be appreciated that there is considerable overlap betweenadditives used in the solid dosage forms described herein. Thus, theabove-listed additives should be taken as merely exemplary, and notlimiting, of the types of additives that can be included in solid dosageforms of the present invention. The amounts of such additives can bereadily determined by one skilled in the art, according to theparticular properties desired.

In other embodiments, one or more layers of the pharmaceuticalformulation are plasticized. Illustratively, a plasticizer is generallya high boiling point solid or liquid. Suitable plasticizers can be addedfrom about 0.01% to about 50% by weight (w/w) of the coatingcomposition. Plasticizers include, but are not limited to, diethylphthalate, citrate esters, polyethylene glycol, glycerol, acetylatedglycerides, triacetin, polypropylene glycol, polyethylene glycol,triethyl citrate, dibutyl sebacate, stearic acid, stearol, stearate, andcastor oil.

Compressed Tablets

Compressed tablets are solid dosage forms prepared by compacting thebulk blend ganaxolone formulations described above. In variousembodiments, compressed tablets which are designed to dissolve in themouth will comprise one or more flavoring agents. In other embodiments,the compressed tablets will comprise a film surrounding the finalcompressed tablet. In some embodiments, the film coating can provide adelayed release of the ganaxolone formulation. In other embodiments, thefilm coating aids in patient compliance (e.g., Opadry® coatings or sugarcoating). Film coatings comprising Opadry® typically range from about 1%to about 3% of the tablet weight. Film coatings for delayed releaseusually comprise 2-6% of a tablet weight or 7-15% of a spray-layeredbead weight. In other embodiments, the compressed tablets comprise oneor more excipients.

Capsule Formulations

A capsule may be prepared, e.g., by placing the bulk blend ganaxoloneformulation, described above, inside of a capsule. In some embodiments,the ganaxolone formulations (non-aqueous suspensions and solutions) areplaced in a soft gelatin capsule. In other embodiments, the ganaxoloneformulations are placed in standard gelatin capsules or non-gelatincapsules such as capsules comprising HPMC. In other embodiments, theganaxolone formulations are placed in a sprinkle capsule, wherein thecapsule may be swallowed whole or the capsule may be opened and thecontents sprinkled on food prior to eating. In some embodiments of thepresent invention, the therapeutic dose is split into multiple (e.g.,two, three, or four) capsules. In some embodiments, the entire dose ofthe ganaxolone formulation is delivered in a capsule form. For example,the capsule may comprise between about 100 mg to about 600 mg ofganaxolone. In some embodiments, the capsule may comprise between about100 to about 500 mg of ganaxolone. In other embodiments, capsule maycomprise about 300 mg to about 400 mg of ganaxolone.

Another useful capsule has a shell comprising the material of therate-limiting membrane, including any of the coating materialspreviously discussed, and filled with ganaxolone particles. A particularadvantage of this configuration is that the capsule may be preparedindependently of the ganaxolone particles, thus process conditions thatwould adversely affect the drug can be used to prepare the capsule. Apreferred embodiment is a capsule having a shell made of a porous or apH-sensitive polymer made by a thermal forming process. An especiallypreferred embodiment is a capsule shell in the form of an asymmetricmembrane; i.e., a membrane that has a thin skin on one surface and mostof whose thickness is constituted of a highly permeable porous material.A preferred process for preparation of asymmetric membrane capsulescomprises a solvent exchange phase inversion, wherein a solution ofpolymer, coated on a capsule-shaped mold, is induced to phase-separateby exchanging the solvent with a miscible non-solvent. Examples ofasymmetric membranes are disclosed in the European Patent Specification0 357 369 B1.

Yet another useful capsule, a “swelling plug device”, can be used.Ganaxolone particles can be incorporated into a non-dissolvingcapsule-half of the device, which is sealed at one end by a hydrogelplug. This hydrogel plug swells in an aqueous environment, and, afterswelling for a predetermined time, exits the capsule thus opening a portthrough which the ganaxolone can leave the capsule and be delivered tothe aqueous environment. Preferred hydrogel-plugged capsules are thosewhich exhibit substantially no release of ganaxolone from the dosageform until the dosage form has exited the stomach and has resided in thesmall intestine for about 15 minutes or greater, preferably about 30minutes or greater, thus assuring that minimal ganaxolone is released inthe stomach. Hydrogel-plugged capsules of this type have been describedin patent application WO90/19168, which is incorporated herein byreference. A ganaxolone swelling plug device may be prepared by loadingganaxolone into a non-dissolving half-capsule shell which may be formedfrom a wide variety of materials, including but not limited topolyethylene, polypropylene, poly(methylmethacrylate),polyvinylchloride, polystyrene, polyurethanes, polytetrafluoroethylene,nylons, polyformaldehydes, polyesters, cellulose acetate, andnitrocellulose. The open end of the capsule shell is then “plugged” witha cylindrical plug formed from a hydrogel-forming material, includingbut not limited to, a homo- or co-poly(alkylene oxide) cross linked byreaction with isocyanate or unsaturated cyclic ether groups, asdescribed in PCT Application WO 90/09168. The composition and length ofthe hydrogel “plug” is selected to minimize release of ganaxolone to thestomach, to decrease the incidence and/or severity of gastrointestinalside effects. The plugged capsule-half is finally sealed with awater-soluble, e.g., gelatin, capsule-half placed over thehydrogel-plugged end of the ganaxolone-containing non-dissolvingcapsule-half. In an embodiment of the “swelling plug device”, the sealeddevice is coated with a pH-sensitive enteric polymer or polymer mixture,for example cellulose acetate phthalate or copolymers of methacrylicacid and methylmethacrylate. The weight of the enteric polymer coat willgenerally be from 2 to 20 wt %, preferably from 4 to 15 wt % of theweight of the uncoated sealed capsule. When this preferred“enteric-coated swelling plug device” is ingested orally, the entericcoat prevents release ganaxolone in the stomach. The enteric coatdissolves quickly, e.g., within about 15 minutes, in the duodenum,triggering swelling of the hydrogel plug, exiting of the hydrogel plug,and release of the incorporated ganaxolone into the gastrointestinaltract at a time greater than about 15 minutes after, and preferablygreater than about 30 minutes after, the dosage form has passed from thestomach into the duodenum. Prototype unfilled “swelling plug devices”may be obtained from Scherer DDS Limited, Clydebank, Scotland, under thedesignation Pulsincap™.

In one embodiment, a ganaxolone formulation comprising dried ganaxoloneparticles can be filled in a capsule. An exemplary process formanufacturing the ganaxolone particles is the milling/evaporationprocess. A Ganaxolone particle suspension comprising 10 to 30 total wt %ganaxolone, 1 to 10 total wt % hydroxypropylmethylcellulose (Pharmacoat603), 0.05 to 0.5 total wt % sodium lauryl sulfate, 0.001 to 0.05 totalwt % simethicone emulsion (30% in water), 0.5 to 5% sucrose and 0.1 to2% NaCl in water is sprayed into a spray granulator using standardparameters known by those skilled in the art. Each wt % is based on thetotal weight of the suspension. The water is evaporated under vacuum ata temperature of 70 to 90° C. The resulting ganaxolone particlescomprise about 50 to 80 wt % of ganaxolone based on the total weight ofthe solid particles. Additional excipients such as magnesium stearate,Mannitol and a disintegrant can be added for flow and re-dispersionproperties. The particles generally have a median particle size (D50) ofabout 50 nm to about 1000 nm, more specifically, about 100 nm to about500 nm. In one embodiment, the capsule is a swelling plug device. Inanother embodiment, the swelling plug device is further coated withcellulose acetate phthalate or copolymers of methacrylic acid andmethylmethacrylate. In another embodiment the capsule is a size 0gelatin capsule.

In another embodiment, a ganaxolone complex formulation comprising adried ganaxolone complex granulation can be filled in a capsule.Ganaxolone complex particle suspension comprising 10 to 30 wt %ganaxolone, 1 to 10 wt % hydroxypropylmethyl cellulose (Pharmacoat 603),0.05 to 0.5 wt % sodium lauryl sulfate, 0.015 to 0.2 wt % paraben suchas methylparaben, 0.001 to 0.05 wt % simethicone emulsion (30% in water)0.5 to 5% sucrose and 0.1 to 2% NaCl in water is pumped into a spraygranulator using standard parameters known by those skilled in the art.Each wt % of the ganaxolone complex particle suspension is based on thetotal weight of the suspension. The water is evaporated under vacuum ata temperature of 70° C. to 90° C. The resulting ganaxolone complexgranulation comprises about 50-80 wt % of ganaxolone based on the totalweight of the solid. Additional excipients such as magnesium stearate,Mannitol and a disintegrant can be added for flow and re-dispersionproperties. The dispersed solid (in SGF or SIF) generally have a medianparticle size (D50) of about 50 nm to about 1000 nm, more specifically,about 100 nm to about 500 nm. In one embodiment, the capsule is aswelling plug device. In another embodiment, the swelling plug device isfurther coated with cellulose acetate phthalate or copolymers ofmethacrylic acid and methylmethacrylate.

In yet another embodiment, spray layered ganaxolone particles or spraylayered ganaxolone complex particles are filled in a capsule. Anexemplary process for manufacturing the spray layered ganaxolone organaxolone complex particles is the fluidized bed spraying process.Ganaxolone suspensions or ganaxolone complex suspensions described aboveare sprayed onto sugar or microcrystalline cellulose (MCC) beads (20-35mesh) with Wurster column insert at an inlet temperature of 50 to 60° C.and air temp of 30 to 50° C. A 15 to 20 wt % total solids contentsuspension containing 45 to 80 wt % ganaxolone, 10 to 25 wt %hydroxymethylpropylcellulose, 0.25 to 2 wt % of SLS, 10 to 18 wt % ofsucrose, 0.01 to 0.3 wt % simethicone emulsion (30% emulsion) and 0.3 to10% NaCl, based on the total weight of the solid content of thesuspension, are sprayed (bottom spray) onto the beads through 1.2 mmnozzles at 10 mL/min and 1.5 bar of pressure until a layering of 400 to700% wt % is achieved as compared to initial beads weight. The resultingspray layered ganaxolone particles or ganaxolone complex particlescomprise about 30 to 70 wt % of ganaxolone based on the total weight ofthe particles. In one embodiment the capsule is a size 0 soft gelatincapsule. In one embodiment, the capsule is a swelling plug device. Inanother embodiment, the swelling plug device is further coated withcellulose acetate phthalate or copolymers of methacrylic acid andmethylmethacrylate.

In some embodiments the capsule includes at least 250 mg (or at least300 mg or at least 400 mg) ganaxolone and has a total weight of lessthan 800 mg (or less that 700 mg). The capsule may contain a pluralityof ganaxolone-containing beads, for example spray layered beads. In someembodiments the beads are 12-25% ganaxolone by weight. In someembodiments some or all of the ganaxolone containing beads are coatedwith a coating comprising 6 to 15% (or 8 to 12%) of the total beadweight. Optimization work typically involves lower loading levels andthe beads constitute 30 to 60% of the finished bead weight. Instead ofor in addition to ganaxolone containing beads the capsule may contain agranulated ganaxolone composition, wherein the granulated compositioncomprises ganaxolone, or ganaxolone, and an ionic dispersion modulator.In some embodiments the compositions additionally comprise a complexingagent and an inorganic or organic salt. For example the granulatedcomposition in some embodiments is comprised of 0.3 to 20% (or 1 to 10%or 1 to 5%) by weight inorganic or organic salt. These granulations alsotypically contain 5 to 30% of a binding agent, 2 to 25% of a watersoluble spacing agent and a wetting agent (0.5 to 2%)

The capsule may be pulsatile release ganaxolone oral dosage form,comprising: (a) a first dosage unit comprising a first ganaxolone dosethat is released substantially immediately following oral administrationof the dosage form to a patient; (b) a second dosage unit comprising asecond ganaxolone dose that is released approximately 3 to 7 hoursfollowing administration of the dosage form to a patient. For pulsatilerelease capsules containing beads the beads can be coated with a coatingcomprising 6 to 15% (or 8 to 12%) of the total bead weight. In someembodiments the coating is a coating that is insoluble at pH 1- to 2 andsoluble at pH greater than 5.5.

In certain embodiments the pulsatile release capsule comprises by weight30 to 50% of the first ganaxolone dose and 50 to 70% of the secondganaxolone dose. This pulsatile release capsule may contain a pluralityof beads in which some beads are immediate release beads and other beadsare formulated, for example with the use of a coating, for modifiedrelease, typically 3 to 10 hours after administration. In otherembodiments the pulsatile release capsule contains a plurality of beadsformulated for modified release and ganaxolone powder, for example spraygranulated ganaxolone, for immediate release.

Formulations Containing Coated Ganaxolone Particles

In some embodiments, the spray layered ganaxolone particles or spraylayered ganaxolone complex particles present in ganaxolone formulations,such as the capsule formulation described above, is coated. Ganaxoloneparticles can be with a modified release coating, such as an entericcoating using cellulose acetate phthalate or copolymers of methacrylicacid and methylmethacrylate. In one embodiment, the enteric coating maybe present in an amount of about 0.5 to 15 wt %, more specifically,about 8 to 12 wt %, based on the weight of the spray layered particles.In one embodiment, the spray layered ganaxolone particles or spraylayered ganaxolone complex particles coated with the enteric coatingscan be filled in a modified release capsule in which both enteric coatedand immediate release ganaxolone beads are filled into a soft gelatincapsule. Additional suitable excipients may also be filled with thecoated particles in the capsule.

In another embodiment, mixtures of spray layered ganaxolone particles orspray layered ganaxolone complex particles coated with the entericcoatings and those without the enteric coatings at appropriate ratiosmay be encapsulated in a suitable immediate release capsule. Theuncoated particles release ganaxolone immediately upon administrationwhile the coated particles do not release ganaxolone until theseparticles reach intestine. By controlling the ratios of the coated anduncoated particles, desirable pulsatile release profiles may beobtained. In some embodiments, the ratios between the uncoated and thecoated particles are 20/80, or 30/70, or 40/60, or 50/50, w/w to obtaindesirable release.

Tablet Spray Layered Dosage Forms

In some embodiments, the spray layered ganaxolone particles or spraylayered ganaxolone complex particles described above can be compressedinto tablets with commonly used pharmaceutical excipients. Anyappropriate apparatus for forming the coating can be used to make theenteric coated tablets, e.g., fluidized bed coating using a wurstercolumn, powder layering in coating pans or rotary coaters; dry coatingby double compression technique; tablet coating by film coatingtechnique, and the like. See, e.g., U.S. Pat. No. 5,322,655; Remington'sPharmaceutical Sciences Handbook: Chapter 90 “Coating of PharmaceuticalDosage Forms”, 1990.

In various embodiments, the spray layered ganaxolone particles or spraylayered ganaxolone complex particles described above and one or moreexcipients are dry blended and compressed into a mass, such as a tablet,having a hardness sufficient to provide a pharmaceutical compositionthat substantially disintegrates within less than about 30 minutes, lessthan about 35 minutes, less than about 40 minutes, less than about 45minutes, less than about 50 minutes, less than about 55 minutes, or lessthan about 60 minutes, after oral administration, thereby releasing theganaxolone formulation into the gastrointestinal fluid.

In other embodiments, the spray layered ganaxolone particles or spraylayered ganaxolone complex particles with enteric coatings describedabove and one or more excipients are dry blended and compressed into amass, such as a tablet. In one embodiment, the enteric coated particlesin the tablet substantially avoids release of ganaxolone, for exampleless than 15 wt %, in the stomach but releases substantially allganaxolone (enterically coated), for example, greater than 80 wt %, inthe intestine.

In yet other embodiments, a pulsatile release ganaxolone formulationcomprises a first dosage unit comprising a formulation made fromganaxolone containing granules made from a spray drying or spraygranulated procedure or a formulation made from ganaxolone complexcontaining granules made from a spray drying or spray granulatedprocedure without enteric coatings and a second dosage unit comprisingspray layered ganaxolone particles or spray layered ganaxolone complexparticles with enteric coatings. In one embodiment, the first dosageunit and the second dosage unit are wet or dry blended and compressedinto a mass to make a pulsatile release tablet. In one embodiment, theweight ratio between the uncoated particles and the coated particles isabout −1:4 to 4:1.

In another embodiment, binding, lubricating and disintegrating agentsare blended (wet or dry) to the spray layered ganaxolone or ganaxolonecomplex spray layered beads to make a compressible blend. The first andthe second dosage units are compressed separately and then compressedtogether to form a bilayer tablet.

In yet another embodiment, the first dosage unit is in the form of anovercoat and completely covers the second dosage unit.

Microencapsulated Formulations

In one aspect of the present invention, dosage forms may includemicroencapsulated ganaxolone formulations. In some embodiments, one ormore other compatible materials are present in the microencapsulationmaterial. Exemplary materials include, but are not limited to,complexing agents, ionic dispersion modulators, pH modifiers, erosionfacilitators, anti-foaming agents, antioxidants, flavoring agents, andcarrier materials such as binders, suspending agents, disintegrationagents, filling agents, surfactants, solubilizers, stabilizers,lubricants, wetting agents, and diluents.

Materials useful for the microencapsulation described herein includematerials compatible with ganaxolone which sufficiently isolateganaxolone from other non-compatible excipients. Materials compatiblewith ganaxolone of the present invention are those that delay therelease of the ganaxolone in vivo.

Exemplary microencapsulation materials useful for delaying the releaseof the formulations comprising ganaxolone include, but are not limitedto, hydroxypropyl cellulose ethers (HPC) such as Klucel® or Nisso HPC,low-substituted hydroxypropyl cellulose ethers (L-HPC), hydroxypropylmethyl cellulose ethers (HPMC) such as Seppifilm-LC, Pharmacoat®,Metolose SR, Methocel®-E, Opadry YS, PrimaFlo, Benecel MP824, andBenecel MP843, methylcellulose polymers such as Methocel®-A,hydroxypropylmethylcellulose acetate stearate Aqoat (HF-LS, HF-LG,HF-MS) and Metolose®, Ethylcelluloses (EC) and mixtures thereof such asE461, Ethocel®, Aqualon®-EC, Surelease®, Polyvinyl alcohol (PVA) such asOpadry AMB, hydroxyethylcelluloses such as Natrosol®,carboxymethylcelluloses and salts of carboxymethylcelluloses (CMC) suchas Aqualon®-CMC, polyvinyl alcohol and polyethylene glycol co-polymerssuch as Kollicoat IR®, monoglycerides (Myverol), triglycerides (KLX),polyethylene glycols, modified food starch, acrylic polymers andmixtures of acrylic polymers with cellulose ethers such as Eudragit®EPO, Eudragit® L30D-55, Eudragit® FS 30D Eudragit® L100-55, Eudragit®L100, Eudragit® S100, Eudragit® RD100, Eudragit® E100, Eudragit® L12.5,Eudragit® S12.5, Eudragit® NE30D, and Eudragit® NE 40D, celluloseacetate phthalate, sepifilms such as mixtures of HPMC and stearic acid,cyclodextrins, parabens, sodium chloride, and mixtures of thesematerials.

In still other embodiments, plasticizers such as polyethylene glycols,e.g., PEG 300, PEG 400, PEG 600, PEG 1450, PEG 3350, and PEG 800,stearic acid, propylene glycol, oleic acid, and triacetin areincorporated into the microencapsulation material. In other embodiments,the microencapsulating material useful for delaying the release of thepharmaceutical compositions is from the USP or the National Formulary(NF). In yet other embodiments, the microencapsulation material isKlucel. In still other embodiments, the microencapsulation material ismethocel.

Microencapsulated ganaxolone may be formulated by methods known by oneof ordinary skill in the art. Such known methods include, e.g., spraydrying processes, spinning disk-solvent processes, hot melt processes,spray chilling methods, spray granulation via fluidized bed,electrostatic deposition, centrifugal extrusion, rotational suspensionseparation, polymerization at liquid-gas or solid-gas interface,pressure extrusion, or spraying solvent extraction bath. In addition tothese, several chemical techniques, e.g., complex coacervation, solventevaporation, polymer-polymer incompatibility, interfacial polymerizationin liquid media, in situ polymerization, in-liquid drying, anddesolvation in liquid media could also be used. Furthermore, othermethods such as roller compaction, extrusion/spheronization,coacervation, or nanoparticle coating may also be used.

The spinning disk method allows for: 1) an increased production rate dueto higher feed rates and use of higher solids loading in feed solution,2) the production of more spherical particles, 3) the production of amore even coating, and 4) limited clogging of the spray nozzle duringthe process.

Spray granulation via a fluid bed is often more readily available forscale-up. In various embodiments, the material used in thespray-granulation encapsulation process is emulsified or dispersed intothe core material in a concentrated form, e.g., 10-60% solids. Themicroencapsulation material is, in one embodiment, emulsified untilabout 1 to 3 μm droplets are obtained. Once a dispersion of ganaxoloneand encapsulation material is obtained, the emulsion is fed as dropletsinto the heated chamber of the spray granulator. In some embodiments,the droplets are sprayed into the chamber or spun off a rotating disk.The microspheres are then dried in the heated chamber and fall to thebottom of the chamber where they are harvested.

Roller compaction, which involves dry granulation of single powder or ablended mixture of powders by the use of pressure to form dense compacts(the compacts are subsequently milled to a desired particle size),provides another alternative. It is a simple process that is readilyavailable for use, and does not involved the use of solvents forgranulation. Thus, roller compaction eliminates the exposure ofsensitive active pharmaceutical ingredients to moisture and drying.Roller compaction can also provide some enhanced stability andtaste-masking characteristics to active pharmaceutical by diluting andisolating such components in a granulated matrix of compatibleingredients. Roller compaction also imparts increased density and flowto the powder.

Extrusion/spheronization is another method that involves wet massing ofactive pharmaceutical ingredients, followed by the extrusion of the wetmass through a perforated plate to produce short cylindrical rods. Theserods are subsequently placed into a rapidly rotating spheronizer toshape the cylindrical rods into uniform spheres. The spheres aresubsequently dried using a fluid bed drier and then coated with afunctional coating using a fluid bed equipped with a Wurster insert andspray nozzle.

Coacervation involves microencapsulation of materials such as activepharmaceutical ingredients and involves a three part process of particleor droplet formation, coacerate wall formation, and capsule isolation.This method can produce very small particle size microcapsules (10-70microns).

In one embodiment, the ganaxolone particles are microencapsulated priorto being formulated into one of the above forms. In still anotherembodiment, some or most of the ganaxolone particles are coated prior tobeing further formulated by using standard coating procedures, such asthose described in Remington's Pharmaceutical Sciences, 20th Edition(2000).

Coated or Plasticized Formulations

In other embodiments, the solid dosage ganaxolone formulations areplasticized (coated) with one or more layers. Illustratively, aplasticizer is generally a high boiling point solid or liquid. Suitableplasticizers can be added from about 0.01% to about 50% by weight (w/w)of the coating composition. Plasticizers include, but are not limitedto, diethyl phthalate, citrate esters, polyethylene glycol, glycerol,acetylated glycerides, triacetin, polypropylene glycol, polyethyleneglycol, triethyl citrate, dibutyl sebacate, stearic acid, stearol,stearate, and castor oil.

In other embodiments a powder comprising the ganaxolone formulationsdescribed herein may be formulated to comprise one or morepharmaceutical excipients and flavors. Such a powder may be prepared,for example, by mixing the ganaxolone formulation and optionalpharmaceutical excipients to form a bulk blend composition. Additionalembodiments also comprise a suspending agent and/or a wetting agent.This bulk blend is uniformly subdivided into unit dosage packaging ormulti-dosage packaging units. The term “uniform” means the homogeneityof the bulk blend is substantially maintained during the packagingprocess. In some embodiments, at least about 75% to about 85% of theganaxolone has an effective particle size by weight of less than 500 nmto about 100 nm. In other embodiments, the ganaxolone comprises at least90% ganaxolone particles having an effective particle size by weight ofless than 500 nm to about 100 nm.

Effervescent Powders

In still other embodiments, effervescent powders are also prepared inaccordance with the present invention. Effervescent salts have been usedto disperse medicines in water for oral administration. Effervescentsalts are granules or coarse powders containing a medicinal agent in adry mixture, usually composed of sodium bicarbonate, citric acid and/ortartaric acid. When salts of the present invention are added to water,the acids and the base react to liberate carbon dioxide gas, therebycausing “effervescence.” Examples of effervescent salts include, e.g:sodium bicarbonate or a mixture of sodium bicarbonate and sodiumcarbonate, citric acid and/or tartaric acid. Any acid-base combinationthat results in the liberation of carbon dioxide can be used in place ofthe combination of sodium bicarbonate and citric and tartaric acids, aslong as the ingredients were suitable for pharmaceutical use and resultin a pH of about 6.0 or higher.

The method of preparation of the effervescent granules of the presentinvention employs three basic processes: wet granulation, drygranulation and fusion. The fusion method is used for the preparation ofmost commercial effervescent powders. It should be noted that, althoughthese methods are intended for the preparation of granules, theformulations of effervescent salts of the present invention could alsobe prepared as tablets, according to known technology for tabletpreparation.

Wet and Dry Granulation

Wet granulation is one of the oldest methods of granule preparation. Theindividual steps in the wet granulation process of tablet preparationinclude milling and sieving of the ingredients, dry powder mixing, wetmassing, granulation, drying and final grinding. In various embodiments,the ganaxolone composition is added to the other excipients of thepharmaceutical formulation after they have been wet granulated.

Dry granulation involves compressing a powder mixture into a roughtablet or “slug” on a heavy-duty rotary tablet press. The slugs are thenbroken up into granular particles by a grinding operation, usually bypassage through an oscillation granulator. The individual steps includemixing of the powders, compressing (slugging) and grinding (slugreduction or granulation). No wet binder or moisture is involved in anyof the steps. In some embodiments, the ganaxolone formulation is drygranulated with other excipients in the pharmaceutical formulation. Inother embodiments, the ganaxolone formulation is added to otherexcipients of the pharmaceutical formulation after they have been drygranulated.

Solid Dispersions

In other embodiments, the ganaxolone formulations described herein aresolid dispersions. Methods of producing such solid dispersions are knownin the art and include, but are not limited to, for example, U.S. Pat.Nos. 4,343,789, 5,340,591, 5,456,923, 5,700,485, 5,723,269, and U.S.Pub. Appl 2004/0013734, each of which is specifically incorporated byreference. In some embodiments, the solid dispersions of the inventioncomprise both amorphous and non-amorphous ganaxolone and can haveenhanced bioavailability as compared to conventional ganaxoloneformulations. In still other embodiments, the ganaxolone formulationsdescribed herein are solid solutions. Solid solutions incorporate asubstance together with the active agent and other excipients such thatheating the mixture results in dissolution of the drug and the resultingcomposition is then cooled to provide a solid blend which can be furtherformulated or directly added to a capsule or compressed into a tablet.Methods of producing such solid solutions are known in the art andinclude, but are not limited to, for example, U.S. Pat. Nos. 4,151,273,5,281,420, and 6,083,518, each of which is specifically incorporated byreference.

Modified Release Forms, Including Controlled Release and Delayed Release

The pharmaceutical solid oral dosage forms comprising the ganaxoloneformulations described herein can be further formulated to provide amodified or controlled release of ganaxolone.

In some embodiments, the solid dosage forms described herein can beformulated as a delay release dosage form such as and enteric coateddelayed release oral dosage forms, i.e., as an oral dosage form of apharmaceutical composition as described herein which utilizes an entericcoating to affect release in the small intestine of the gastrointestinaltract. The enteric coated dosage form may be a compressed or molded orextruded tablet/mold (coated or uncoated) containing granules, powder,pellets, beads or particles of the active ingredient and/or othercomposition components, which are themselves coated or uncoated. Theenteric coated oral dosage form may also be a capsule (coated oruncoated) containing pellets, beads or granules of the solid carrier orthe composition, which are themselves coated or uncoated. Entericcoatings may also be used to prepare other controlled release dosageforms including extended release and pulsatile release dosage forms.

In other embodiments, the ganaxolone formulations described herein aredelivered using a pulsatile dosage form. Pulsatile dosage formscomprising the ganaxolone formulations described herein may beadministered using a variety of formulations known in the art. Forexample, such formulations include, but are not limited to, thosedescribed in U.S. Pat. Nos. 5,011,692, 5,017,381, 5,229,135, and5,840,329, each of which is specifically incorporated by reference.Other dosage forms suitable for use with the ganaxolone formulations aredescribed in, for example, U.S. Pat. Nos. 4,871,549, 5,260,068,5,260,069, 5,508,040, 5,567,441 and 5,837,284, all of which arespecifically incorporated by reference. In one embodiment, thecontrolled release dosage form is pulsatile release solid oral dosageform comprising at least two groups of particles, each containing theganaxolone formulation described herein. The first group of particlesprovides a substantially immediate dose of ganaxolone upon ingestion bya subject. The first group of particles can be either uncoated orcomprise a coating and/or sealant. The second group of particlescomprises coated particles, which comprise from about 2% to about 75%,preferably from about 2.5% to about 70%, and more preferably from about40% to about 70%, by weight of the total dose of the ganaxolone in saidformulation, in admixture with one or more binders. The coatingcomprises a pharmaceutically acceptable ingredient in an amountsufficient to provide a delay of from about 2 hours to about 7 hoursfollowing ingestion before release of the second dose. Suitable coatingsinclude one or more differentially degradable coatings such as, by wayof example only, pH sensitive coatings (enteric coatings) such asacrylic resins (e.g., Eudragit® EPO, Eudragit® L30D-55, Eudragit® FS 30DEudragit® L100-55, Eudragit® L100, Eudragit® 5100, Eudragit® RD100,Eudragit® E100, Eudragit® L12.5, Eudragit® S12.5, and Eudragit® NE30D,Eudragit® NE 40D®) either alone or blended with cellulose derivatives,e.g., ethylcellulose, or non-enteric coatings having variable thicknessto provide differential release of the ganaxolone formulation.

Many other types of controlled release systems known to those ofordinary skill in the art and are suitable for use with the ganaxoloneformulations described herein. Examples of such delivery systemsinclude, e.g., polymer-based systems, such as polylactic andpolyglycolic acid, plyanhydrides and polycaprolactone; porous matrices,nonpolymer-based systems that are lipids, including sterols, such ascholesterol, cholesterol esters and fatty acids, or neutral fats, suchas mono-, di- and triglycerides; hydrogel release systems; silasticsystems; peptide-based systems; wax coatings, bioerodible dosage forms,compressed tablets using conventional binders and the like. See, e.g.,Liberman et al., Pharmaceutical Dosage Forms, 2 Ed., Vol. 1, pp. 209-214(1990); Singh et al., Encyclopedia of Pharmaceutical Technology, 2^(nd)Ed., pp. 751-753 (2002); U.S. Pat. Nos. 4,327,725, 4,624,848, 4,968,509,5,461,140, 5,456,923, 5,516,527, 5,622,721, 5,686,105, 5,700,410,5,977,175, 6,465,014 and 6,932,983, each of which is specificallyincorporated by reference.

In another embodiment, a modified release dosage formulation maycomprise a combination of: (a) a compressed tablet core comprising apoorly water soluble active agent, a pharmaceutically acceptable waterswellable polymer, and an osmotic agent; and (b) an outer coating layerwhich completely covers the tablet core and comprises a pH sensitivecoating. An optional sealing coat may be applied to the compressedtablet core and an optional coating layer comprising an enteric coatingagent may be applied under the outer coating layer as an inner coatingor as an overcoat over the outer coating layer. The tablet core may becompressed using a smooth faced tablet die. In one embodiment, theactive agent is ganaxolone.

The osmotic agent in this dosage form is any non-toxic pharmaceuticallyacceptable water soluble compound which will dissolve sufficiently inwater and increase the osmotic pressure inside the tablet core. Suitableosmotic agents include simple sugars and salts such as sodium chloride,potassium chloride, magnesium sulfate, magnesium sulfate, magnesiumchloride, sodium sulfate, lithium sulfate, urea, inositol, sucrose,lactose, glucose, sorbitol, fructose, mannitol, dextrose, magnesiumsuccinate, potassium acid phosphate and the like. The preferred osmoticagent for the tablet core is a simple sugar such as anhydrous lactose inthe range of 0-50% by weight, based on the weight of the compressed,uncoated tablet.

The water swellable polymer may be any pharmaceutically acceptablepolymer which swells and expands in the presence of water to slowlyrelease ganaxolone. These polymers include polyethylene oxide,methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcelluloseand the like. In a preferred embodiment, the water swellable polymerwill be polyethylene oxide (obtained from Union Carbide Corporationunder the trade name Polyox WSR Coagulant or Polyox WSR N 80). Thesematerials form a viscous gel in water or other solvent system at asufficient concentration to control the release of the ganaxolone. Thiswill generally require a concentration of the pharmaceuticallyacceptable, water swellable polymer of about 0-50% by weight of thecompressed, uncoated tablet.

The outer coating comprises a pH sensitive coating which functions as anenteric polymer in that it does not begin to dissolve until pHconditions in excess of the pH of the stomach region are encountered.The pH sensitive coating is the same type of material that is describedabove. The pH sensitive coating may be present in an amount of about0.5-15 wt %, more specifically, about 8-12 wt %, based on the weight ofthe coated tablet core.

Certain controlled release formulation may release less than about 20 wt% of ganaxolone in the formulation is released within the first threehours after administration and more than about 60 percent of ganaxolonebetween 3 and 10 hours. Other controlled release ganaxolone formulationmay release less than about 50 percent within the first three hoursafter administration and about 50 percent of ganaxolone between 3 and 10hours.

Enteric Coatings

Enteric coatings should be applied to a sufficient thickness such thatthe entire coating does not appreciably dissolve in the gastrointestinalfluids at pH below about 5 after 1 hour, but does dissolve at pH about 5and above. It is expected that any anionic polymer exhibiting apH-dependent solubility profile can be used as an enteric coating in thepractice of the present invention to achieve delivery to the lowergastrointestinal tract. In some embodiments the polymers for use in thepresent invention are anionic carboxylic polymers. In other embodiments,the polymers and compatible mixtures thereof, and some of theirproperties, include, but are not limited to:

Shellac, also called purified shellac, a refined product obtained fromthe resinous secretion of an insect. This coating dissolves in media ofpH>7;

Acrylic polymers. The performance of acrylic polymers (primarily theirsolubility in biological fluids) can vary based on the degree and typeof substitution. Examples of suitable acrylic polymers includemethacrylic acid copolymers and ammonia methacrylate copolymers. TheEudragit series E, L, S, RL, RS and NE (Rohm Pharma) are available assolubilized in organic solvent, aqueous dispersion, or dry powders. TheEudragit series RL, NE, and RS are insoluble in the gastrointestinaltract but are permeable and are used primarily for colonic targeting.The Eudragit series E dissolve in the stomach. The Eudragit series L,L-30D and S are insoluble in stomach and dissolve in the intestine;Opadry Enteric are also insoluble in stomach and dissolve in theintestine.

Cellulose Derivatives. Examples of suitable cellulose derivatives are:ethyl cellulose; reaction mixtures of partial acetate esters ofcellulose with phthalic anhydride. The performance can vary based on thedegree and type of substitution. Cellulose acetate phthalate (CAP)dissolves in pH>6. Aquateric (FMC) is an aqueous based system and is aspray dried CAP psuedolatex with particles<1 μm. Other components inAquateric can include pluronics, Tweens, and acetylated monoglycerides.Other suitable cellulose derivatives include: cellulose acetatetrimellitate (Eastman); methylcellulose (Pharmacoat, Methocel);hydroxypropylmethyl cellulose phthalate (HPMCP); hydroxypropylmethylcellulose succinate (HPMCS); and hydroxypropylmethylcellulose acetatesuccinate (e.g., AQOAT (Shin Etsu)). The performance can vary based onthe degree and type of substitution. For example, HPMCP such as, HP-50,HP-55, HP-55S, HP-55F grades are suitable. The performance can varybased on the degree and type of substitution. For example, suitablegrades of hydroxypropylmethylcellulose acetate succinate include, butare not limited to, AS-LG (LF), which dissolves at pH 5, AS-MG (MF),which dissolves at pH 5.5, and AS-HG (HF), which dissolves at higher pH.These polymers are offered as granules, or as fine powders for aqueousdispersions;

PolyVinyl Acetate Phthalate (PVAP). PVAP dissolves in pH>5 and it ismuch less permeable to water vapor and gastric fluids.

In some embodiments, the coating can, and usually does, contain aplasticizer and possibly other coating excipients such as colorants,talc, and/or magnesium stearate, which are well known in the art.Suitable plasticizers include triethyl citrate (Citroflex 2), triacetin(glyceryl triacetate), acetyl triethyl citrate (Citroflec A2), Carbowax400 (polyethylene glycol 400), diethyl phthalate, tributyl citrate,acetylated monoglycerides, glycerol, fatty acid esters, propyleneglycol, and dibutyl phthalate. In particular, anionic carboxylic acrylicpolymers usually will contain 10-25% by weight of a plasticizer,especially dibutyl phthalate, polyethylene glycol, triethyl citrate andtriacetin. Conventional coating techniques such as spray or pan coatingare employed to apply coatings. The coating thickness must be sufficientto ensure that the oral dosage form remains intact until the desiredsite of topical delivery in the intestinal tract is reached.

Colorants, detackifiers, surfactants, antifoaming agents, lubricants(e.g., carnuba wax or PEG) may be added to the coatings besidesplasticizers to solubilize or disperse the coating material, and toimprove coating performance and the coated product.

A particularly suitable methacrylic copolymer is Eudragit L®,particularly L-30D® and Eudragit 100-55®, manufactured by Rohm Pharma,Germany. In Eudragit L-30D®, the ratio of free carboxyl groups to estergroups is approximately 1:1. Further, the copolymer is known to beinsoluble in gastrointestinal fluids having pH below 5.5, generally1.5-5.5, i.e., the pH generally present in the fluid of the uppergastrointestinal tract, but readily soluble or partially soluble at pHabove 5.5, i.e., the pH values present in the small intestine.

In some embodiments, materials include shellac, acrylic polymers,cellulosic derivatives, polyvinyl acetate phthalate, and mixturesthereof. In other embodiments, materials include Eudragit® series E, L,RL, RS, NE, L, L300, S, 100-55, cellulose acetate phthalate, Aquateric,cellulose acetate trimellitate, ethyl cellulose,hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcelluloseacetate succinate, polyvinyl acetate phthalate, and Cotteric.

Liquid Formulations

In some embodiments, pharmaceutical ganaxolone formulations are providedcomprising the ganaxolone particles described herein and at least onedispersing agent or suspending agent for oral administration to asubject. The ganaxolone formulation may be a powder and/or granules forsuspension, and upon admixture with water, a substantially uniformsuspension is obtained. As described herein, the aqueous dispersion cancomprise amorphous and non-amorphous ganaxolone particles of consistingof multiple effective particle sizes such that ganaxolone particleshaving a smaller effective particle size are absorbed more quickly andganaxolone particles having a larger effective particle size areabsorbed more slowly. In certain embodiments the aqueous dispersion orsuspension is an immediate release formulation. In another embodiment,an aqueous dispersion comprising amorphous ganaxolone particles isformulated such that about 50% of the ganaxolone particles are absorbedwithin about 3 hours after administration and about 90% of theganaxolone particles are absorbed within about 10 hours afteradministration. In other embodiments, addition of a complexing agent tothe aqueous dispersion results in a larger span of ganaxolone containingparticles to extend the drug absorption phase such that 50-80% of theparticles are absorbed in the first 3 hours and about 90% are absorbedby about 10 hours.

A suspension is “substantially uniform” when it is mostly homogenous,that is, when the suspension is composed of approximately the sameconcentration of ganaxolone at any point throughout the suspension.Preferred embodiments are those that provide concentrations essentiallythe same (within 15%) when measured at various points in a ganaxoloneaqueous oral formulation after shaking. Especially preferred are aqueoussuspensions and dispersions, which maintain homogeneity (up to 15%variation) when measured 2 hours after shaking. The homogeneity shouldbe determined by a sampling method consistent with regard to determininghomogeneity of the entire composition. In one embodiment, an aqueoussuspension can be re-suspended into a homogenous suspension by physicalagitation lasting less than 1 minute. In another embodiment, an aqueoussuspension can be re-suspended into a homogenous suspension by physicalagitation lasting less than 45 seconds. In yet another embodiment, anaqueous suspension can be re-suspended into a homogenous suspension byphysical agitation lasting less than 30 seconds. In still anotherembodiment, no agitation is necessary to maintain a homogeneous aqueousdispersion.

In some embodiments, the ganaxolone powders for aqueous dispersiondescribed herein comprise stable ganaxolone particles having aneffective particle size by weight of less than 500 nm formulated withganaxolone particles having an effective particle size by weight ofgreater than 500 nm. In such embodiments, the formulations have aparticle size distribution wherein about 10% to about 100% of theganaxolone particles by weight are between about 75 nm and about 500 nm,about 0% to about 90% of the ganaxolone particles by weight are betweenabout 150 nm and about 400 nm, and about 0% to about 30% of theganaxolone particles by weight are greater than about 600 nm. Theganaxolone particles describe herein can be amorphous, semi-amorphous,crystalline, semi-crystalline, or mixture thereof.

In one embodiment, the aqueous suspensions or dispersions describedherein comprise ganaxolone particles or ganaxolone complex at aconcentration of about 20 mg/ml to about 150 mg/ml of suspension. Inanother embodiment, the aqueous oral dispersions described hereincomprise ganaxolone particles or ganaxolone complex particles at aconcentration of about 25 mg/ml to about 75 mg/ml of solution. In yetanother embodiment, the aqueous oral dispersions described hereincomprise ganaxolone particles or ganaxolone complex at a concentrationof about 50 mg/ml of suspension. The aqueous dispersions describedherein are especially beneficial for the administration of ganaxolone toinfants (less than 2 years old), children under 10 years of age and anypatient group that is unable to swallow or ingest solid oral dosageforms.

Liquid ganaxolone formulation dosage forms for oral administration canbe aqueous suspensions selected from the group including, but notlimited to, pharmaceutically acceptable aqueous oral dispersions,emulsions, solutions, and syrups. See, e.g., Singh et al., Encyclopediaof Pharmaceutical Technology, 2^(nd) Ed., pp. 754-757 (2002). Inaddition to ganaxolone particles, the liquid dosage forms may compriseadditives, such as: (a) disintegrating agents; (b) dispersing agents;(c) wetting agents; (d) at least one preservative, (e) viscosityenhancing agents, (f) at least one sweetening agent, (g) at least oneflavoring agent, (h) a complexing agent, and (i) an ionic dispersionmodulator. In some embodiments, the aqueous dispersions can furthercomprise a crystalline inhibitor.

Examples of disintegrating agents for use in the aqueous suspensions anddispersions include, but are not limited to, a starch, e.g., a naturalstarch such as corn starch or potato starch, a pregelatinized starchsuch as National 1551 or Amijel®, or sodium starch glycolate such asPromogel® or Explotab®; a cellulose such as a wood product,microcrystalline cellulose, e.g., Avicel®, Avicel® PH101, Avicel® PH102,Avicel® PH105, Elcema® P100, Emcocel®, Vivacel®, Ming Tia®, andSolka-Floc®, methylcellulose, croscarmellose, or a cross-linkedcellulose, such as cross-linked sodium carboxymethylcellulose(Ac-Di-Sol®), cross-linked carboxymethylcellulose, or cross-linkedcroscarmellose; a cross-linked starch such as sodium starch glycolate; across-linked polymer such as crosspovidone; a cross-linkedpolyvinylpyrrolidone; alginate such as alginic acid or a salt of alginicacid such as sodium alginate; a clay such as Veegum® HV (magnesiumaluminum silicate); a gum such as agar, guar, locust bean, Karaya,pectin, or tragacanth; sodium starch glycolate; bentonite; a naturalsponge; a surfactant; a resin such as a cation-exchange resin; citruspulp; sodium lauryl sulfate; sodium lauryl sulfate in combinationstarch; and the like.

In some embodiments, the dispersing agents suitable for the aqueoussuspensions and dispersions described herein are known in the art andinclude, for example, hydrophilic polymers, electrolytes, Tween® 60 or80, PEG, polyvinylpyrrolidone (PVP; commercially known as Plasdone®),and the carbohydrate-based dispersing agents such as, for example,hydroxypropylcellulose and hydroxypropylcellulose ethers (e.g., HPC,HPC-SL, and HPC-L), hydroxypropylmethylcellulose andhydroxypropylmethylcellulose ethers (e.g. HPMC K100, HPMC K4M, HPMCK15M, and HPMC K100M), carboxymethylcellulose sodium, methylcellulose,hydroxyethylcellulose, hydroxypropylmethylcellulose phthalate,hydroxypropylmethylcellulose acetate stearate, noncrystalline cellulose,magnesium aluminum silicate, triethanolamine, polyvinyl alcohol (PVA),polyvinylpyrrolidone/vinyl acetate copolymer (Plasdone®, e.g., S-630),4-(1,1,3,3-tetramethylbutyl)-phenol polymer with ethylene oxide andformaldehyde (also known as tyloxapol), poloxamers (e.g., PluronicsF68®, F88®, and F108®, which are block copolymers of ethylene oxide andpropylene oxide); and poloxamines (e.g., Tetronic 908®, also known asPoloxamine 908®, which is a tetrafunctional block copolymer derived fromsequential addition of propylene oxide and ethylene oxide toethylenediamine (BASF Corporation, Parsippany, N.J.)). In otherembodiments, the dispersing agent is selected from a group notcomprising one of the following agents: hydrophilic polymers;electrolytes; Tween® 60 or 80; PEG; polyvinylpyrrolidone (PVP);hydroxypropylcellulose and hydroxypropyl cellulose ethers (e.g., HPC,HPC-SL, and HPC-L); hydroxypropyl methylcellulose and hydroxypropylmethylcellulose ethers (e.g. HPMC K100, HPMC K4M, HPMC K15M, HPMC K100M,and Pharmacoat® USP 2910 (Shin-Etsu)); carboxymethylcellulose sodium;methylcellulose; hydroxyethylcellulose; hydroxypropylmethyl-cellulosephthalate; hydroxypropylmethyl-cellulose acetate stearate;non-crystalline cellulose; magnesium aluminum silicate; triethanolamine;polyvinyl alcohol (PVA); 4-(1,1,3,3-tetramethylbutyl)-phenol polymerwith ethylene oxide and formaldehyde; poloxamers (e.g., Pluronics F68®,F88®, and F108®, which are block copolymers of ethylene oxide andpropylene oxide); or poloxamines (e.g., Tetronic 908®, also known asPoloxamine 908®).

Wetting agents (including surfactants) suitable for the aqueoussuspensions and dispersions described herein are known in the art andinclude, but are not limited to, acetyl alcohol, glycerol monostearate,polyoxyethylene sorbitan fatty acid esters (e.g., the commerciallyavailable Tweens® such as e.g., Tween 20® and Tween 80® (ICI SpecialtyChemicals)), and polyethylene glycols (e.g., Carbowaxs 3350® and 1450®,and Carpool 934® (Union Carbide)), oleic acid, glyceryl monostearate,sorbitan monooleate, sorbitan monolaurate, triethanolamine oleate,polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitanmonolaurate, sodium oleate, sodium lauryl sulfate, sodium docusate,triacetin, vitamin E TPGS, sodium taurocholate, simethicone,phosphotidylcholine and the like.

Suitable preservatives for the aqueous suspensions or dispersionsdescribed herein include, for example, potassium sorbate, parabens(e.g., methylparaben and propylparaben) and their salts, benzoic acidand its salts, other esters of parahydroxybenzoic acid such asbutylparaben, alcohols such as ethyl alcohol or benzyl alcohol, phenoliccompounds such as phenol, or quaternary compounds such as benzalkoniumchloride. Preservatives, as used herein, are incorporated into thedosage form at a concentration sufficient to inhibit microbial growth.In one embodiment, the aqueous liquid dispersion can comprisemethylparaben and propylparaben in a concentration ranging from about0.01% to about 0.3% methylparaben by weight to the weight of the aqueousdispersion and 0.005% to 0.03% propylparaben by weight to the totalaqueous dispersion weight. In yet another embodiment, the aqueous liquiddispersion can comprise methylparaben 0.05 to about 0.1 weight % andpropylparaben from 0.01-0.02 weight % of the aqueous dispersion.

Suitable viscosity enhancing agents for the aqueous suspensions ordispersions described herein include, but are not limited to, methylcellulose, xanthan gum, carboxymethylcellulose, hydroxypropyl cellulose,hydroxypropylmethyl cellulose, Plasdone® S-630, carbomer, polyvinylalcohol, alginates, acacia, chitosans and combinations thereof. Theconcentration of the viscosity enhancing agent will depend upon theagent selected and the viscosity desired.

Examples of natural and artificial sweetening agents suitable for theaqueous suspensions or dispersions described herein include, forexample, acacia syrup, acesulfame K, alitame, anise, apple, aspartame,banana, Bavarian cream, berry, black currant, butterscotch, calciumcitrate, camphor, caramel, cherry, cherry cream, chocolate, cinnamon,bubble gum, citrus, citrus punch, citrus cream, cotton candy, cocoa,cola, cool cherry, cool citrus, cyclamate, cylamate, dextrose,eucalyptus, eugenol, fructose, fruit punch, ginger, glycyrrhetinate,glycyrrhiza (licorice) syrup, grape, grapefruit, honey, isomalt, lemon,lime, lemon cream, monoammonium glyrrhizinate (MagnaSweet®), maltol,mannitol, maple, marshmallow, menthol, mint cream, mixed berry,neohesperidine DC, neotame, orange, pear, peach, peppermint, peppermintcream, Prosweet® Powder, raspberry, root beer, rum, saccharin, safrole,sorbitol, spearmint, spearmint cream, strawberry, strawberry cream,stevia, sucralose, sucrose, sodium saccharin, saccharin, aspartame,acesulfame potassium, mannitol, talin, sucralose, sorbitol, Swiss cream,tagatose, tangerine, thaumatin, tutti fruitti, vanilla, walnut,watermelon, wild cherry, wintergreen, xylitol, or any combination ofthese flavoring ingredients, e.g., anise-menthol, cherry-anise,cinnamon-orange, cherry-cinnamon, chocolate-mint, honey-lemon,lemon-lime, lemon-mint, menthol-eucalyptus, orange-cream, vanilla-mint,and mixtures thereof. In one embodiment, the aqueous liquid dispersioncan comprise a sweetening agent or flavoring agent in a concentrationranging from about 0.0001% to about 10.0% the weight of the aqueousdispersion. In another embodiment, the aqueous liquid dispersion cancomprise a sweetening agent or flavoring agent in a concentrationranging from about 0.0005% to about 5.0% wt % of the aqueous dispersion.In yet another embodiment, the aqueous liquid dispersion can comprise asweetening agent or flavoring agent in a concentration ranging fromabout 0.0001% to 0.1 wt %, from about 0.001% to about 0.01 weight %, orfrom 0.0005% to 0.004% of the aqueous dispersion.

In addition to the additives listed above, the liquid ganaxoloneformulations can also comprise inert diluents commonly used in the art,such as water or other solvents, solubilizing agents, and emulsifiers.

Emulsions

In some embodiments, the pharmaceutical ganaxolone formulationsdescribed herein can be self-emulsifying drug delivery systems (SEDDS).Emulsions are dispersions of one immiscible phase in another, usually inthe form of droplets. Generally, emulsions are created by vigorousmechanical dispersion. SEDDS, as opposed to emulsions or microemulsions,spontaneously form emulsions when added to an excess of water withoutany external mechanical dispersion or agitation. An advantage of SEDDSis that only gentle mixing is required to distribute the dropletsthroughout the solution. Additionally, water or the aqueous phase can beadded just prior to administration, which ensures stability of anunstable or hydrophobic active ingredient. Thus, the SEDDS provides aneffective delivery system for oral and parenteral delivery ofhydrophobic active ingredients. SEDDS may provide improvements in thebioavailability of hydrophobic active ingredients. Methods of producingself-emulsifying dosage forms are known in the art include, but are notlimited to, for example, U.S. Pat. Nos. 5,858,401, 6,667,048, and6,960,563, each of which is specifically incorporated by reference.

Exemplary emulsifiers are ethyl alcohol, isopropyl alcohol, ethylcarbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propyleneglycol, 1,3-butyleneglycol, dimethylformamide, sodium lauryl sulfate,sodium doccusate, cholesterol, cholesterol esters, taurocholic acid,phosphotidylcholine, oils, such as cottonseed oil, groundnut oil, corngerm oil, olive oil, castor oil, and sesame oil, glycerol,tetrahydrofurfuryl alcohol, polyethylene glycols, fatty acid esters ofsorbitan, or mixtures of these substances, and the like.

Intranasal Formulations

Intranasal formulations are known in the art and are described in, forexample, U.S. Pat. Nos. 4,476,116, 5,116,817 and 6,391,452, each ofwhich is specifically incorporated by reference. Ganaxolone formulationsprepared according to these and other techniques well-known in the artare prepared as solutions in saline, employing benzyl alcohol or othersuitable preservatives, fluorocarbons, and/or other solubilizing ordispersing agents known in the art. See, for example, Ansel, H. C. etal., Pharmaceutical Dosage Forms and Drug Delivery Systems, Sixth Ed.(1995). Preferably these compositions and formulations are prepared withsuitable nontoxic pharmaceutically acceptable ingredients. Theseingredients are known to those skilled in the preparation of nasaldosage forms and some of these can be found in REMINGTON: THE SCIENCEAND PRACTICE OF PHARMACY, 21st edition, 2005, a standard reference inthe field. The choice of suitable carriers is highly dependent upon theexact nature of the nasal dosage form desired, e.g., solutions,suspensions, ointments, or gels. Nasal dosage forms generally containlarge amounts of water in addition to the active ingredient. Minoramounts of other ingredients such as pH adjusters, emulsifiers ordispersing agents, preservatives, surfactants, gelling agents,complexing agents or buffering and other stabilizing and solubilizingagents may also be present. Preferably, the nasal dosage form should beisotonic with nasal secretions.

Buccal Formulations

Buccal formulations comprising the ganaxolone formulations describedherein may be administered using a variety of formulations known in theart. For example, such formulations include, but are not limited to,U.S. Pat. Nos. 4,229,447, 4,596,795, 4,755,386, and 5,739,136, each ofwhich is specifically incorporated by reference. In addition, the buccaldosage forms described herein can further comprise a bioerodible(hydrolyzable) polymeric carrier that may also serves to adhere thedosage form to the buccal mucosa. The buccal dosage form is fabricatedso as to erode gradually over a predetermined time period, whereinganaxolone delivery is provided essentially throughout. Buccal drugdelivery, as will be appreciated by those skilled in the art, avoids thedisadvantages encountered with oral drug administration, e.g., slow drugabsorption, degradation of the active agent by fluids present in thegastrointestinal tract and/or first-pass inactivation in the liver. Withregard to the bioerodible (hydrolysable) polymeric carrier, it will beappreciated that virtually any such carrier can be used, so long as thedesired drug release profile is not comprised, and the carrier iscompatible with ganaxolone and any other components that may be presentin the buccal dosage unit. Generally, the polymeric carrier compriseshydrophilic (water-soluble and water-swellable) polymers that adhere tothe wet surface of the buccal mucosa. Examples of polymeric carriersuseful herein include acrylic acid polymers and co, e.g., those known as“carbomers” (Carbopol®, which may be obtained from B.F. Goodrich, is onesuch polymer). Other components may also be incorporated into the buccaldosage forms described herein include, but are not limited to,disintegrants, diluents, binders, lubricants, flavoring, colorants,preservatives, and the like.

Transdermal Formulations

Transdermal formulations described herein may be administered using avariety of devices which have been described in the art. For example,such devices include, but are not limited to, U.S. Pat. Nos. 3,598,122,3,598,123, 3,710,795, 3,731,683, 3,742,951, 3,814,097, 3,921,636,3,972,995, 3,993,072, 3,993,073, 3,996,934, 4,031,894, 4,060,084,4,069,307, 4,077,407, 4,201,211, 4,230,105, 4,292,299, 4,292,303,5,336,168, 5,665,378, 5,837,280, 5,869,090, 6,923,983, 6,929,801 and6,946,144, each of which is specifically incorporated by reference inits entirety. In some embodiments, the transdermal delivery device usedwith the ganaxolone formulations described herein can comprise a powersource, radio frequency, or a brief electrical current tomicro-electrodes in the skin creating “channels” or “pores” in thestratum corneum to facilitate the delivery of the ganaxoloneformulation, such methods are known in the art and are described in, forexample U.S. Pat. Nos. 6,611,706, 6,708,060, and 6,711,435, each ofwhich is specifically incorporated by reference in its entirety. Inother embodiments, the transdermal delivery device can comprise a meansfor porating the stratum corneum, e.g., micro-lancing, application ofsonic energy, or hydraulic puncturing, to facilitate the delivery of theganaxolone formulation, such methods are known in the art and aredescribed in, for example, U.S. Pat. Nos. 6,142,939 and 6,527,716, eachof which is specifically incorporated by reference in its entirety. Thepores described by the methods herein are typically about 20-50 micronsin depth and to not extend into areas of innervation or vascularization.

The transdermal dosage forms described herein may incorporate certainpharmaceutically acceptable excipients which are conventional in theart. In general, the transdermal formulations described herein compriseat least three components: (1) a ganaxolone or ganaxolone complexformulation; (2) a penetration enhancer; and (3) an aqueous adjuvant. Inaddition, transdermal formulations can include additional componentssuch as, but not limited to, gelling agents, creams and ointment bases,and the like. In some embodiments, the transdermal formulation canfurther comprise a woven or non-woven backing material to enhance drugabsorption and prevent the removal of the transdermal formulation fromthe skin. In other embodiments, the transdermal formulations describedherein can maintain a saturated or supersaturated state to promotediffusion into the skin.

Injectable Formulations

Ganaxolone formulations suitable for intramuscular, subcutaneous, orintravenous injection may comprise physiologically acceptable sterileaqueous or non-aqueous solutions, dispersions, suspensions or emulsions,and sterile powders for reconstitution into sterile injectable solutionsor dispersions. Examples of suitable aqueous and non-aqueous carriers,diluents, solvents, or vehicles including water, ethanol, polyols(propylene glycol, polyethylene-glycol, glycerol, cremophor and thelike), suitable mixtures thereof, vegetable oils (such as olive oil) andinjectable organic esters such as ethyl oleate. Additionally, Ganaxolonecan be dissolved at concentrations of >1 mg/ml using water soluble betacyclodextrins (e.g. beta-sulfobutyl-cyclodextrin and2-hydroxypropylbetacyclodextrin. Proper fluidity can be maintained, forexample, by the use of a coating such as lecithin, by the maintenance ofthe required particle size in the case of dispersions, and by the use ofsurfactants. Ganaxolone formulations suitable for subcutaneous injectionmay also contain additives such as preserving, wetting, emulsifying, anddispensing agents. Prevention of the growth of microorganisms can beensured by various antibacterial and antifungal agents, such asparabens, benzoic acid, benzyl alcohol, chlorobutanol, phenol, sorbicacid, and the like. It may also be desirable to include isotonic agents,such as sugars, sodium chloride, and the like. Prolonged drug absorptionof the injectable pharmaceutical form can be brought about by the use ofagents delaying absorption, such as aluminum monostearate and gelatin.Ganaxolone suspension formulations designed for extended release viasubcutaneous or intramuscular injection can avoid first pass metabolismand lower dosages of ganaxolone will be necessary to maintain plasmalevels of about 50 ng/ml. In such formulations, the particle size of theganaxolone particles and the range of the particle sizes of theganaxolone particles can be used to control the release of the drug bycontrolling the rate of dissolution in fat or muscle.

V. Sterile Ganaxolone Formulations

Some of the ganaxolone formulations described herein can be sterilefiltered. This property obviates the need for heat sterilization, whichcan harm or degrade ganaxolone, as well as result effective particlesize growth.

Sterile filtration can be difficult because of the required smallparticle size of the composition. However, this method is suitable andcommonly used for dispersions comprising nanoparticles. Filtration is aneffective method for sterilizing homogeneous solutions when the membranefilter pore size is less than or equal to about 0.2 microns (200 nm)because a 0.2 micron filter is sufficient to remove essentially allbacteria. Sterile filtration is normally not used to sterilizeconventional suspensions of micron-sized ganaxolone because theganaxolone particles are too large to pass through the membrane pores.

Because Some of the ganaxolone-complex formulations described herein canbe sterilized via autoclaving, and because the formulations can have avery small ganaxolone effective average particle size, some sterilizedganaxolone formulations are suitable for parenteral administration.Additionally, a sterile ganaxolone formulation is particularly useful intreating immunocompromised patients, infants or juvenile patients,patients with head trauma and the elderly.

VI. Combination Therapies

The compositions and methods described herein may also be used inconjunction with other well known therapeutic reagents that are selectedfor their particular usefulness against the condition that is beingtreated. In general, the compositions described herein and, inembodiments where combinational therapy is employed, other agents do nothave to be administered in the same pharmaceutical composition, and may,because of different physical and chemical characteristics, have to beadministered by different routes. The determination of the mode ofadministration and the advisability of administration, where possible,in the same pharmaceutical composition, is well within the knowledge ofthe skilled clinician. The initial administration can be made accordingto established protocols known in the art, and then, based upon theobserved effects, the dosage, modes of administration and times ofadministration can be modified by the skilled clinician.

The particular choice of compounds used will depend upon the diagnosisof the attending physicians and their judgment of the condition of thepatient and the appropriate treatment protocol. The compounds may beadministered concurrently (e.g., simultaneously, essentiallysimultaneously or within the same treatment protocol) or sequentially,depending upon the nature of the proliferative disease, the condition ofthe patient, and the actual choice of compounds used. The determinationof the order of administration, and the number of repetitions ofadministration of each therapeutic agent during a treatment protocol, iswell within the knowledge of the skilled physician after evaluation ofthe disease being treated and the condition of the patient.

It is understood that the dosage regimen to treat, prevent, orameliorate the condition(s) for which relief is sought, can be modifiedin accordance with a variety of factors. These factors include thedisorder from which the subject suffers, as well as the age, weight,sex, diet, and medical condition of the subject. Thus, the dosageregimen actually employed can vary widely and therefore can deviate fromthe dosage regimens set forth herein.

The pharmaceutical agents which make up the combination therapydisclosed herein may be a combined dosage form or in separate dosageforms intended for substantially simultaneous administration. Thepharmaceutical agents that make up the combination therapy may also beadministered sequentially, with either therapeutic compound beingadministered by a regimen calling for two-step administration. Thetwo-step administration regimen may call for sequential administrationof the active agents or spaced-apart administration of the separateactive agents. The time period between the multiple administration stepsmay range from, a few minutes to several hours, depending upon theproperties of each pharmaceutical agent, such as potency, solubility,bioavailability, plasma half-life and kinetic profile of thepharmaceutical agent. Circadian variation of the target moleculeconcentration may also determine the optimal dose interval.

In some embodiments, the ganaxolone formulation is administered with atleast one other anti-convulsant agent. In other embodiments, theganaxolone formulation is administered with at least one otheranti-epileptic agent. In still other embodiments, the ganaxoloneformulation is administered with at least one other anti-anxiety agent.In yet other embodiments, the ganaxolone formulation is administeredwith at least one other anti-depression agent.

VII. Pharmacokinetic Profiles of the Ganaxolone Formulations

The ganaxolone formulations and dosage forms described herein displaypharmacokinetic profiles that can result in C_(min) ganaxolone bloodplasma levels at steady state from about 10 ng/ml to about 100 ng/ml. Inone embodiment, the ganaxolone formulations described herein provideblood plasma levels immediately prior to the next dose (C_(min)) atsteady state from about 25 ng/ml to about 100 ng/ml. In anotherembodiment, the ganaxolone formulations described herein provide C_(min)blood plasma levels at steady state from about 40 ng/ml to about 75ng/ml. In yet another embodiment, the ganaxolone formulations describedherein provide C_(min) blood plasma levels at steady state of about 50ng/ml. In addition to the improved steady state pharmacokinetics, thepresent ganaxolone formulations can provide controlled release ofganaxolone such that the C_(max)/C_(min) ratio blood plasma levels ofganaxolone is less than or equal to 4 at steady state for an orallyadministered dispersion and 3 or less with a solid dosage form. In oneembodiment, the ganaxolone formulations described herein provide for thecontrolled release of ganaxolone such that the C_(max)/C_(mm) ratioblood plasma levels of ganaxolone ranges from about 1.5 to 3.5 at steadystate. In another embodiment, the ganaxolone formulations describedherein provide for the controlled release of ganaxolone such that theC_(max)/C_(min) ratio blood plasma level of ganaxolone is about 3.0 atsteady state.

VIIa. Increased Ganaxolone Exposure

The ganaxolone formulations and dosage forms described herein exhibit,in one particular aspect, increased exposure in the fasted state ascompared to prior conventional ganaxolone formulations administered atthe same dose under the same conditions.

As previously stated, elevated blood plasma levels of ganaxolone canresult in undesirable side effects. Thus, lower doses of ganaxolonewhich can achieve the same or better therapeutic effects as thoseobserved with larger doses of conventional ganaxolone formulations aredesired. Such lower doses can be realized with the ganaxoloneformulations described herein as a result of the greater exposureobserved with the present ganaxolone formulations as compared toconventional ganaxolone formulations. The ganaxolone formulationsdescribed herein exhibit exposure in the fasted state as compared toconventional ganaxolone formulations in a range of between at leastabout 100% and about 500%, preferably between about 150% and about 300%,of the specified therapeutic parameter (e.g., AUC 0-∞ or AUC_((0-τ))when τ is greater or equal to 24 hours. In one embodiment, theganaxolone formulation is an aqueous dispersion exhibiting abioavailability in the fasted state as compared to conventionalganaxolone formulations in a range of between about 150% and about 300%.In another embodiment, the ganaxolone formulation is an oral soliddosage form exhibiting a exposure in the fasted state as compared toconventional ganaxolone formulations in a range of between about 150%and about 400%. In still another embodiment, the ganaxolone formulationis an intranasal dosage form exhibiting enhanced pharmacodynamic effectsas compared to a similar oral dose of the conventional formulation. Inyet another embodiment, the ganaxolone formulation is a buccal dosageform exhibiting a exposure as compared to conventional ganaxoloneformulations in a range of between about 200% and about 800%.

For example, Monaghan et al. have previously published that conventionalganaxolone formulations administered to human subjects in a high fat fedstate display pharmacokinetic profiles such that the AUC_((0-∞)) bloodplasma values ranges from about 1,564±566 (ng/h/ml) to about 2826±316(ng/h/ml) with doses of 900 mg to 1500 mg, respectfully. By comparison,the AUC_((0-∞)) blood plasma values of an administered dose of 900 mg to1500 mg of the ganaxolone formulation described herein is at least 50%higher than the AUC_((0-∞)) blood plasma values exhibited byconventional formulation of ganaxolone administered in the fasted stateat the same dosage under the same conditions.

VIIIb. Reduced C_(max)/C_(min) Blood Plasma Ratios of Ganaxolone

The ganaxolone formulations described herein can exhibit reducedC_(max)/C_(min) blood plasma ratios of ganaxolone at steady state ascompared to conventional ganaxolone formulations administered at thesame dose under the same conditions. For example, Monaghan et al. havepreviously published that conventional ganaxolone formulations displaypharmacokinetic profiles such that multiple doses of conventionalganaxolone formulations given over the course of 14 days resulted inC_(max)/C_(min) blood plasma ratios of ganaxolone of 13.8 (50 mg), 4.4(200 mg), and 6.7 (500 mg). By comparison, for some embodiments of theinvention the C_(max)/C_(min) blood plasma ratios of the ganaxoloneformulations described herein are less than 4 at steady state. In oneembodiment, the ganaxolone formulations described herein provide forC_(max)/C_(min) blood plasma ratios of ganaxolone range from about 1.5to 3.5 at steady state. In another embodiment, the ganaxoloneformulations described herein provide C_(max)/C_(min) blood plasmaratios of ganaxolone of about 2.5 at steady state. In some embodiments,a transdermal ganaxolone formulation provides C_(max)/C_(min) bloodplasma ratios of ganaxolone of less than 1.5 at steady state.

VIIIc. Controlled Exposure Profiles

In certain embodiments, about 40% of the ganaxolone is released from thedosage form within about 3 hours and about 95% of the ganaxolone isreleased from the dosage form within about 10 hours afteradministration. In yet another embodiment, about 30% of the ganaxoloneis released from the dosage form within about 3 hours and about 90% ofthe ganaxolone is released from the dosage form within about 10 hoursafter administration. In yet another embodiment, about 80% of theganaxolone is released from the dosage form within about 2 hours andabout 90% of the ganaxolone is released from the dosage form withinabout 10 hours after administration.

VIIId. Reduced Fed/Fasted Effects Associated with the Administration ofGanaxolone

It is generally known in the art that if a positive fed/fasted effect isseen with a pharmaceutical agent, it is typically related to the dose ofthe active agent administered such that a lower dose of an active agentwill have a lower ratio of AUC_((fed))/AUC_((fasted)) and a higher doseof an active agent will have a higher ratio ofAUC_((fed))/AUC_((fasted)). In addition, it is known that dosage formswhich substantially eliminate the effects of food on the therapeuticwindow (levels for efficacy vs. levels giving side effects) are saferthan those dosage forms which do not. Thus dosage forms that providereduced fed/fasted effects provide decreased risks and reduce thepotential for side effects, thereby increasing subject safety andcompliance. Fed/fasted conditions are in accordance with FDA guidelinesfor testing drug exposure in the fed and fasted states.

Conventional formulations of ganaxolone display large fed/fasted effectsin a manner that is not limited to dose dependency. The ganaxoloneformulations described herein are less effected by the fed or fastedstate of the subject being administered the formulation. The systemicexposure of the ganaxolone formulations described herein is lesssensitive to the type of meal ingested than conventional ganaxoloneformulations. This means that there is a reduced difference in theAUC_((0-τ)) values of ganaxolone when the ganaxolone formulations areadministered in the fed versus the fasted state at therapeuticallyeffective doses. Thus, described herein are ganaxolone formulations thatcan substantially reduce the effect of food on the pharmacokinetics ofganaxolone. In one embodiment, the ganaxolone formulation is an aqueousdispersion that when administered to a human under two years old,provides a ratio of the AUC_((0-∞)) or AUC_((0-τ)) values of ganaxolone,when administered in the fed versus the fasted state, of less than about4. In another embodiment, the ganaxolone formulation is a solid oraldosage form that when administered to a human over twelve years oldprovides a the ratio of the AUC_((0-τ)) values of ganaxolone, whenadministered in the fed versus the fasted state, of less than about 3.In still another embodiment, the ganaxolone formulation is a solid oraldosage form that when administered to a human over twelve years oldprovides a ratio of the AUC_((0-τ)) values of ganaxolone, whenadministered in the fed versus the fasted state, of less than about 2.In yet another embodiment, the ganaxolone formulation is a solid oraldosage form that when administered to a human over twelve years oldprovides a ratio of the AUC_((0-τ)) values of ganaxolone, whenadministered in the fed versus the fasted state, of less than about 1.5.In still another embodiment, the ganaxolone formulation is a solid oraldosage form that when administered to a human over twelve years oldprovides a ratio of the AUC_((0-τ)) values of ganaxolone, whenadministered in the fed versus the fasted state, ranging from about 3 toabout 1.5. In another embodiment, the ganaxolone formulation is a solidoral dosage form that when administered to a human over twelve years oldprovides a ratio of the AUC_((0-τ)) values of ganaxolone, whenadministered in the fed versus the fasted state, of about 2.

VIII. Dose Amounts

The ganaxolone formulations described herein are administered and dosedin accordance with good medical practice, taking into account theclinical condition of the individual patient, the site and method ofadministration, scheduling of administration, and other factors known tomedical practitioners. In human therapy, the dosage forms describedherein deliver ganaxolone formulations that maintain a therapeuticallyeffective amount of ganaxolone of at least 20 ng/ml or typically atleast about 50 ng/ml in plasma at steady state while reducing the sideeffects associated with an elevated C_(max) blood plasma level ofganaxolone.

In various other embodiments of the present invention, the amountganaxolone administered to a subject via a solid dosage form to achievea therapeutically effective concentration ganaxolone is typically in therange of about 50 mg to about 800 mg or from about 300 mg to about 700mg. In one embodiment, a ganaxolone formulation is administered in asolid dosage form at a concentration of about 250 mg to about 650 mg. Inanother embodiment, the ganaxolone formulation is administered in asolid dosage form at concentration of about 300-400 mg. In anotheraspect, the solid oral dosage form can be administered twice a day(b.i.d). In yet another aspect, the solid oral dosage form is acontrolled release dosage form administered b.i.d. providing a pulsatilerelease of ganaxolone such that the C_(max) of blood plasma ganaxoloneis reduced to avoid adverse effects while simultaneously reducingfed/fasted effects and maintaining total exposure (AUC_((0-∞)).

A therapeutically effective concentration of an oral aqueous suspensionor dispersion comprising a ganaxolone formulation described herein,administered according to the methods described herein, is typically inthe range of about 20 mg/ml to about 150 mg/ml final concentration. Inone embodiment, a ganaxolone formulation is administered as an aqueousoral suspension at a concentration of about 25 mg/ml to about 100 mg/mlfinal concentration. In another embodiment, a ganaxolone formulation isadministered as an aqueous oral suspension at a concentration of about50 mg/ml final concentration. The aqueous oral suspensions comprising aganaxolone formulation described herein can be administered both as asingle dose per day or given multiple times within a 24 hour period. Inone aspect, the aqueous oral suspension can be administered three timesa day (t.i.d). In another aspect, the aqueous oral suspension can beadministered twice a day (b.i.d.).

Contemplated compositions of the present invention provide atherapeutically effective amount of ganaxolone over an interval of about30 minutes to about 8 hours after administration, enabling, for example,once-a-day, twice-a-day, three times a day, and etc. administration ifdesired.

In further embodiments, greater than about 95%; or greater than about90%; or greater than about 80%; or greater than about 70% of theganaxolone dosed by weight is absorbed into the bloodstream within 8hours after administration.

In other embodiments, the pharmaceutical formulations provide a releaseprofile for an immediate release dosage form of the ganaxolone, wherebyusing methods described in Example 29, whereby about 804% (or about 70%or about 90%) of the ganaxolone is released from the dosage form withinabout 1 hours in SGF and for a delay release ganaxolone dosage formabout 60% of the (or preferably 70% or 80%) is released from thecomposition within about 3 hours in SGF.

IX. Methods of Manufacturing Ganaxolone Formulations ComprisingSubmicron Particles

The ganaxolone formulations described herein can comprise ganaxoloneparticles having a D50 of less than about 500 nm. The startingganaxolone composition can be predominantly crystalline, predominantlyamorphous, or a mixture thereof. These ganaxolone particles can be madeby using any method known in the art for achieving particle sizes ofless than 500 nm including, for example, milling, homogenization,supercritical fluid fracture or precipitation techniques. Exemplarymethods are described in U.S. Pat. Nos. 4,540,602 and 5,145,684, each ofwhich is specifically incorporated by reference.

Methods of making compositions comprising nanoparticles are alsodescribed in U.S. Pat. Nos. 5,518,187; 5,718,388; 5,862,999; 5,665,331;5,662,883; 5,560,932; 5,543,133; 5,534,270; 5,510,118; 5,470,583 andU.S. Pub. Appl. 2004/0067251, each of which is specifically incorporatedby reference.

A. Milling to Obtain Ganaxolone Dispersions Comprising SubmicronParticles

The milling process can be a dry process, e.g., a dry roller millingprocess, or a wet process, i.e., wet-grinding. In some embodiments, thisinvention is practiced in accordance with the wet-grinding processdescribed in U.S. Pat. Nos. 4,540,602, 5,145,684, 6,976,647 and EPO498,482, the disclosures of which are hereby incorporated by reference.Thus, the wet grinding process can be practiced in conjunction with aliquid dispersion medium and dispersing or wetting agents such asdescribed in these publications. Useful liquid dispersion media includewater, safflower oil, aqueous salt solutions, ethanol, n-butanol,hexane, glycol and the like. The dispersing, and/or wetting agents canbe selected from known organic and inorganic pharmaceutical excipientssuch as described in U.S. Pat. Nos. 4,540,602 and 5,145,684, and can bepresent in an amount of 2.0-70%, preferably 3-50%, and more preferably5-25% by weight based on the total weight of formulation.

The grinding media for the particle size reduction step can be selectedfrom rigid media preferably spherical or particulate in shape, e.g.,beads. However, grinding media in the form of other non-spherical shapesare expected to be useful in the practice of this invention.

The grinding media preferably can have a mean particle size up to about500 microns. In other embodiments of the invention, the grinding mediaparticles have a mean particle size preferably less than about 500microns, less than about 100 microns, less than about 75 microns, lessthan about 50 microns, less than about 25 microns, less than about 5microns, less than about 3 mm, less than about 2 mm, less than about 1mm, less than about 0.25 mm, or less than about 0.05 mm. For finegrinding, the grinding media particles preferably are from about 0.05 toabout 0.6 mm, more preferably, about 0.1 to about 0.4 mm in size.Smaller size grinding media will result in smaller size drug particlesas compared to the same conditions using larger sized grinding media.

In selecting material, grinding media with higher density, e.g., glass(2.6 g/cm³), zirconium silicate (3.7 g/cm³), and zirconium oxide (5.4g/cm³), are generally preferred for more efficient milling. Zirconiumoxide, such as 95% Zirconium oxide stabilized with magnesia, zirconiumsilicate, and glass grinding media provide particles having levels ofcontamination which are believed to be acceptable for the preparation oftherapeutic or diagnostic compositions. However, other media, such asstainless steel, titania, agate, glass, alumina, and approx. 95%zirconium oxide stabilized with yttrium, are believed to be useful. Inaddition, polymeric media having a density typically from about 1 toabout 2 g/cm³ are also expected to be useful.

If polymeric grinding media is utilized, then the grinding media cancomprise particles consisting essentially of the polymeric resin.Alternatively, the grinding media can comprise particles comprising acore having a coating of the polymeric resin adhered thereon. Thepolymeric resin preferably has a density from 0.8 to 3.0 g/cm³. Higherdensity resins are preferred inasmuch as it is believed that theseprovide more efficient particle size reduction.

In general, polymeric resins suitable for use herein are chemically andphysically inert, substantially free of metals, solvent and monomers,and of sufficient hardness and friability to enable them to avoid beingchipped or crushed during grinding. Suitable polymeric resins includebut are not limited to crosslinked polystyrenes, such as polystyrenecrosslinked with divinylbenzene, styrene copolymers, polycarbonates,polyacetals, such as Delrin™, vinyl chloride polymers and copolymers,polyurethanes, polyamides, poly(tetrafluoroethylenes), e.g., Teflon™,and other fluoropolymers, high density polyethylenes, polypropylenes,cellulose ethers and esters such as cellulose acetate,polyhydroxymethacrylate, polyhydroxyethyl acrylate, silicone containingpolymers such as polysiloxanes, and the like. The polymeric polymer canbe biodegradable. Exemplary biodegradable polymeric polymers includepoly(lactides), poly(glycolide) copolymers of lactides and glycolide,polyanhydrides, poly(hydroxyethyl methacylate), poly(imino carbonates),poly(N-acylhydroxyproline)esters, poly(N-palmitoyl hydroxyproline)esters, ethylene-vinyl acetate copolymers, poly(orthoesters),poly(caprolactones), and poly(phosphazenes). In the case ofbiodegradable polymers, contamination from the media itselfadvantageously can metabolize in vivo into biologically acceptableproducts which can be eliminated from the body.

The core material preferably can be selected from materials known to beuseful as grinding media when fabricated as spheres or particles.Suitable core materials include but are not limited to zirconium oxides(such as 95% zirconium oxide stabilized with magnesia or yttrium),zirconium silicate, glass, stainless steel, titania, alumina, ferrite,and the like. Preferred core materials have a density greater than about2.5 g/cm³. The selection of high density core materials is believed tofacilitate efficient particle size reduction.

Useful thicknesses of the polymeric polymer coating on the core arebelieved to range from about 1 to about 500 microns, although otherthicknesses outside this range may be useful in some applications. Thethickness of the polymer coating preferably is less than the diameter ofthe core.

The cores can be coated with the polymeric resin by techniques known inthe art. Suitable techniques include spray coating, fluidized bedcoating, and melt coating. Adhesion promoting or tie layers canoptionally be provided to improve the adhesion between the core materialand the resin coating. The adhesion of the polymer coating to the corematerial can be enhanced by treating the core material to adhesionpromoting procedures, such as roughening of the core surface, coronadischarge treatment, and the like.

In some embodiments, ganaxolone can be prepared in submicron particlesize, e.g., less than about 500 nm. In certain embodiments, theparticles can be prepared having an effective particle size by weight ofless than about 400 nm. In certain embodiments, particles having aneffective particle size by weight of less than 300 nm can be prepared inaccordance with the present invention. In other embodiments, particleshaving an effective particle size by weight of less than 200 nm andabout 100 nm can be prepared in accordance with the present invention.

Grinding can take place in any suitable grinding mill. Suitable millsinclude an airjet mill, a roller mill, a ball mill, an attritor mill, avibratory mill, a planetary mill, a sand mill and a bead mill. A highenergy media mill is preferred when small particles are desired. Themill can contain a rotating shaft.

The preferred proportions of the grinding media, ganaxolone, theoptional liquid dispersion medium, and dispersing, wetting or otherparticle stabilizing agents present in the grinding vessel can varywithin wide limits and depends, for example, the size and density of thegrinding media, the type of mill selected, the time of milling, etc. Theprocess can be carried out in a continuous, batch or semi-batch mode. Inhigh energy media mills, it can be desirable to fill 80-95% of thevolume of the grinding chamber with grinding media. On the other hand,in roller mills, it frequently is desirable to leave the grinding vesselup to half filled with air, the remaining volume comprising the grindingmedia and the liquid dispersion media, if present. This permits acascading effect within the vessel on the rollers which permitsefficient grinding. However, when foaming is a problem during wetgrinding, the vessel can be completely filled with the liquid dispersionmedium or an anti-foaming agent may be added to the liquid dispersion.

The attrition time can vary widely and depends primarily upon theparticular drug substance or imaging agent, mechanical means andresidence conditions selected, the initial and desired final particlesize and so forth. For roller mills, processing times from several daysto weeks may be required. On the other hand, milling residence times ofless than about 2 hours are generally required using high energy mediamills.

After attrition is completed, the grinding media is separated from themilled ganaxolone particulate product (in either a dry or liquiddispersion form) using conventional separation techniques, such as byfiltration, sieving through a mesh screen, and the like.

In one aspect of the invention, the grinding media comprises beadshaving a size ranging from 0.05-4 mm, preferably 0.1-0.4 mm. Forexample, high energy milling of ganaxolone with yttrium stabilizedzirconium oxide 0.4 mm beads for a milling residence time of 25 minutesto 1.5 hours in recirculation mode at 2500 RPM. In another example, highenergy milling of ganaxolone with 0.1 mm zirconium oxide balls for amilling residence time of 2 hours in batch mode. Additionally, themilling temperature should not exceed 50° C. as the viscosity of thesuspension may change dramatically. Elevated temperatures also mayresult in precipitation of certain polymers in the milling slurry andwill increase wear on the mill seals. If supplies of milled suspensionexceeds the void milling chamber volume then this process will requirerecycling the material to a cooled holding tank and re-milling of thematerial until the desired particle (D50) size and appropriateproperties are achieved in continuous mode and the mill is also jacketedwith cooling. In another aspect, the mill can be jacketed to helpcontrol internal temperatures in both continuous or batch mode. Themilling concentration is from about 10% to about 30% ganaxolone byweight vs. the milling media weight. The milling media is defined as theweight of the slurry that is milled minus the weight of the drug in thatslurry. In one embodiment, the concentration is 25% ganaxolone by weightvs. the milling media (weight). In one embodiment, the milling mediacontains at least one agent to adjust viscosity so that the desiredparticles are suspended evenly, and a wetting and/or dispersing agent tocoat the initial ganaxolone suspension so a uniform feed rate may beapplied in continuous milling mode. In another embodiment, batch millingmode is utilized with a milling media containing at least one agent toadjust viscosity and/or provide a wetting effect so that the ganaxoloneis well dispersed amongst the grinding media.

Xa. Milling to Obtain Stable Particles

A concern with the preparation of any small particle suspension is thestability of the milled particles. The milled particles after a periodof time (e.g., four weeks) after milling may tend to agglomerate andresult in increased particle size as compared to the particles sizeimmediately after milling. When creating small particle formulations(<500 nm) most compositions never stabilize and continue to grow untillarge particles (1-30 microns) are realized. The rate at which theseparticles grow depends on the composition and the residence time ofmilling. The art around producing small particle compositions of organicmolecules has focused on various methods and compositions to suppressparticle growth or aggregation. One unanticipated and novel conceptdiscussed herein is adding complexing agent(s) to initially providerapid particle size growth over a curing period which then becomes avery stable small molecule formulation. This growth in particle size isespecially observed initially after adding methylparaben with or withoutpropylparaben or benzoic acid/sodium benzoate. A non-preservativecomplexing agent is methylanthranilate.

The final stable particle size as measured by volume-weighted-median(D50) is dependent upon the concentration of the complexing agentsand/or milling residence time. When the concentration of complexingagents was kept constant, the post-milling growth of particlescorrelates closely with residence time. Therefore, certain aspects ofthe present invention are directed to the unexpected observation thatthe residence time that the active agent particles (e.g., ganaxoloneparticles) are subjected to during the milling process, has an impact onthe variability of the subsequent growth in particles size aftermilling.

The milling residence time is defined by the following equation:Milling Residence Time=(milling chamber void volume/milling slurryvolume)×milling time  (Equation 1).

Within Equation 1 the void chamber volume is the void space in the millchamber that can be occupied by the milling slurry. It is calculated byestimating the bead void space in the beads (for 0.4 mmyttrium-stabilized zirconium oxide beads, the bead void space isapproximately 36-40% of the beads volume) and void chamber volume is thevolume of the milling chamber−the volume of the beads+the bead voidspace (all in the same volume units). When milling under re-circulatingconditions (passing multiple times through a mill by creating a loopbetween a milling slurry in a vessel and the mill, the disclosedresidence times are obtained using flow rates varying from ¼ of theestimated void volume/minute to 3 times (3×) the estimated void chambervolume/minute. Ideally flow rates of 0.5× void chamber volume per minuteto 1.5× void volume per minute are used.

As demonstrated in the examples, it has been observed that afterobtaining a desired particle size, continued milling which does notsignificantly reduce the particle size any further, does produce moregrowth stable particles as compared to the shorter milling residencetime. Ganaxolone complex particle size can be controlled by the amountof complexing agent or by re-milling stable particles after curing. SeeExample 45, which shows that re-milling stabilizes ganaxolone complexparticle size. One factor that may contribute to the growth of theparticle size is the association of a complexing agent with a ganaxoloneparticle. It is also possible that this complex can further associatewith other particle excipients, e.g., a viscosity enhancing agent orwetting agent. These complexes which are initially reversible undersonication, harden over time to become larger, permanent particles. (SeeFIG. 1). The curing time is the time needed for the complex to hardenand become a stable particle. The effect of the milling residence timemay affect the variability of size growth due to that prolonged millingproduces more particles with smoother surfaces that have less area forcontact and are less prone to aggregation. As will be shown below, onecan obtain stable ganaxolone suspensions containing particles with D50'sof 100-350 nm by milling a slurry for less time and adding a complexingagent or by milling a slurry at higher speeds for longer periods oftime.

With the understanding that milling residence time has a significantimpact on ganaxolone stability additional milling experiments wereperformed. The objectives of the additional milling experiments were (a)to prepare ganaxolone formulations comprising particles having a rangeof particle sizes including particles with a volume-weighted D50 of lessthan 500 nm; (b) to prepare ganaxolone formulations comprising particleswith D50 of less than 500 nm containing at least one complexing agent;(c) to prepare ganaxolone formulations comprising particles of (a) and(b) that show minimal particle size growth in simulated gastric andintestinal fluids at 36-38° C.; (d) to prepare ganaxolone formulationscomprising particles of (a) to (c) that are flavored with artificialflavoring, sweetened with a sweetener, preserved to pass anti-microbialeffectiveness testing and other ingredients to enhance palatability. Theresults of these experiments are presented at the Examples section.

Based on this unexpected observation, certain embodiments of the presentinvention provide pharmaceutical particles comprising ganaxolone thereofwhich exhibit a stable growth profile over time, i.e., the particlesprovide a ratio of D50 four weeks after milling or 4 weeks after acuring period if a complexing agent is added to D50 at the end ofmilling of 1.5:1 or less. The novel nature of adding a small moleculecomplexing agent is seen in some embodiments where one can reproduciblyincrease the particle size mode (highest populated particle size) byabout 2-fold in 5-7 days. After this period the particle size and modeis stable for many months.

Certain embodiments of the invention also provide a method ofstabilizing the particle growth of pharmaceutical particles comprisingmilling an active agent (including, but not limited to ganaxolonethereof) for a sufficient time for the particles to provide a ratio ofD50 four weeks after milling to D50 at the end of milling of 1.5:1 orless.

In further embodiments, the particles have a ratio of D50 four monthsafter curing or after a long milling residence time to of about 1.25:1or less; or about 1.15:1 or less.

In order for the milled ganaxolone particles of the present invention toprovide a growth stable profile with ganaxolone particles in the 100-350nm range (D50), the particles have a preferred milling residence time ofat least 40 minutes if a complexing agent is added, at least 100minutes, or at least 120 minutes without a complexing agent added.However, these times are not meant to be limiting. The residence timenecessary for obtaining a growth stable formulation can be ascertainedby one of skill in the art, given the guidance provided by the presentdisclosure.

The resultant particles of the milling process disclosed herein can havea D50 of less than 500 nm, less than 400 nm, less than 300 nm, less than200 nm or less than 100 nm. The resultant particles can also have a D90of less than 1 micron, less than 500 nm, less than 400 nm, less than 300nm, less than 200 nm.

For stable particle compositions disclosed herein, the particles canoptionally include a complexing agent as disclosed herein. Thecomplexing agent can be a preservative such as methylparaben,propylparaben, benzoic acid/sodium benzoate, a phenolic compound, anorganic acid, an organic acid salt, an inorganic acid, an inorganicsalt, or a combination thereof.

The processes utilized to obtain the stable particles can be anyprocedure known to one skilled in the art for producing small particles,e.g., the processes described in Section IXA herein.

The end product of the milling processes to obtain growth stableparticles can comprise the active agent particles suspended in adispersing agent (i.e., a suspension).

Xb. Complexing Agents as Particle Growth Stabilizers

Addition of a complexing agent during or preferably post-milling wasfound to improve the physical stability of ganaxolone particlesformulations (e.g. liquid suspension formulations). The improvement inphysical stability is believed to be the result of the formation ofcomplex's of ganaxolone particles and the complexing agent which causesan increase in ganaxolone particle size. Without being bound by theory,it is hypothesized that the increase in ganaxolone particle size incomplexing agent containing formulations is achieved through a particlecomplex forming process. For example, the complexing agent(s) can act asan aggregating or binding agent for ganaxolone particles to stick toeach other or to form a ganaxolone-aggregates associated with thecomplexing agent and possibly other ingredients in the suspension. Theseaggregates are relatively week during the early stages (first 2-3 days)of the complex formation, e.g. in the case of adding methylparaben ormethylparaben and propylparaben or parabens and benzoic acid/sodiumbenzoate

This is evident as sonication of the formulation in this stage canreduce the particle size of the complex, apparently due to the loosenature of the newly-formed complexes. Over a period of time, theaggregates harden, or cure, and the particle size of the aggregatescannot be reduced by sonication. At this point, the curing process iscomplete. This complex forming process is illustrated in FIG. 1.

Different complexing agents affect the complex formations differently.Formulations are given as wt %/w (weight %/total formulation weight).

The cured ganaxolone-particles appear to have much better physicalstability than ganaxolone particles that do not contain the complexingagent. Once the ganaxolone particle complexes are formed, no furthersubstantial increase in ganaxolone particle size is observed. Ganaxoloneparticles that were milled for less than 2 hours milling residence timeand do not contain complexing agents continue to increase gradually insize over a number of months (FIG. 3.).

Addition of a complexing agent during or preferably post-milling wasfound to improve the physical stability of ganaxolone particlesformulations (e.g. liquid suspension formulations). The improvement inphysical stability is believed to be the result of the formation ofcomplex's of ganaxolone particles and the complexing agent which causesan increase in ganaxolone particle size. Without being bound by theory,it is hypothesized that the increase in ganaxolone particle size incomplexing agent containing formulations is achieved through a particlecomplex forming process. For example, the complexing agent(s) can act asan aggregating or binding agent for ganaxolone particles to stick toeach other or to form a ganaxolone-aggregates associated with thecomplexing agent and possibly other ingredients in the suspension. Theseaggregates are relatively weak during the early stages (first 2-3 days)of the complex formation, e.g. in the case of adding methylparaben, ormethylparaben and propylparaben, or parabens and benzoic acid/sodiumbenzoate. This is evident as sonication of the formulation in this stagecan reduce the particle size of the complex, apparently due to the loosenature of the newly-formed complexes. Over a period of time, theaggregates harden, or cure, and the particle size of the aggregatescannot be reduced by sonication. At this point, the curing process iscomplete. This complex forming process is illustrated in FIG. 1.

The particle size range (in addition to milling residence time) prior tocontact with the particles growth stabilizer also affects the aggregatecuring process. In some embodiments, ganaxolone particles of about 140nm grew to about 300 nm after curing. On the other hand, ganaxoloneparticles of about 300 nm only grew to about 350 nm after curing.

In certain embodiments, the complexing agent can be a preservative. Thecomplexing agent is selected from the group consisting of organic acids,carboxylic acids, acid salts of amino acids, sodium metabisulphite,ascorbic acid and its derivatives, malic acid, isoascorbic acid, citricacid, tartaric acid, sodium sulphite, sodium bisulfate, tocopherol,water- and fat-soluble derivatives of tocopherol, sulphites, bisulphitesand hydrogen sulphites, anthranilic acid and esters thereof,para-aminobezoic acid and esters,2,6-di-t-butyl-alpha-dimethylamino-p-cresol, t-butylhydroquinone,di-t-amylhydroquinone, di-t-butylhydroquinone, butylhydroxytoluene(BHT), butylhydroxyanisole (BHA), methylparaben, ethylparaben,propylparaben as well as the paraben salts, pyrocatechol, pyrogallol,propyl/gallate, and nordihydroguaiaretic acid, phosphoric acids,phenols, sorbic and benzoic acids, sodium benzoates, esters, derivativesand isomeric compounds, ascorbyl palmitate, pharmaceutically acceptablesalts thereof, and mixtures thereof.

Parabens are esters of para-hydroxybenzoic acid. Parabens which can beutilized in the present invention include methylparaben, ethylparaben,propylparaben, and butylparaben. Other parabens which can be utilized inthe present invention include isobutylparaben, isopropylparaben,benzylparaben. Pharmaceutically acceptable salts, e.g., sodium andpotassium salts, can also be utilized in the present invention.Especially preferred parabens for use in the present invention includemethylparaben and propylparaben and their sodium salts. If the sodiumsalts of parabens are utilized an equimolar amount of an organic acid,e.g., citric acid should be added. Further evidence that methyl andpropyl paraben are acting as a complexing agent is that in the preferredembodiments where 25 wt % ganaxolone containing 0.1%-0.3% sodium laurylsulfate and 2-5 wt % HPMC (Pharmacoat 603) are milled with a residencetime of 35-40 minutes with a particle size D50 range from 120-170 nm and0.1% methylparaben and 0.02% propylparaben are added, the particle sizemode (most populated particle size range) approximately doubles, thecomposition becomes visibly thick and not possible to filter through 5um or below filters and after 5-10 days, the particles stop growing andstable particles are realized. As will be shown later, the complexed andcured particles exhibit other desirable attributes that thenon-complexed formulations do not have. More compelling evidence of therole of methylparaben and propylparaben in the formation of Ganaxoloneparticle complexes is that running anti-microbial effectiveness studiesunder USP conditions shows a typical preservative effect during thefirst 7-14 days, which is then lost and microbial growth rebounds asthere is little methylparaben and propylparaben available to act as apreservative. In fact the preferred ganaxolone oral suspensions use twoor three preservatives to obtain sufficient anti-microbial effectivenessto pass US and European preservative testing.

The complexing agent can be present in any suitable amount, e.g., fromabout 0.001% to about 5%, from about 0.01% to about 2.5%, from about0.015% to about 1%, from about 0.1% to about 0.5% or from about 0.02% toabout 0.1%, based on the weight of the milled slurry.

Certain embodiments of the invention are directed to the initialparticle growth due to the association of the ganaxolone particles andthe complexing agent. These embodiments are directed to pharmaceuticalparticles comprising ganaxolone thereof associated with a complexingagent, the particles exhibiting a ratio of D50 after incubation in SGFor SIF at 36-38° C. for 1-3 hours to D50 prior to SGF or SIF incubationof less than about 3:1; less than about 2.7:1, less than about 2.5:1,less than about 2:1, or less than about 1.5:1. In certain embodiments,the invention is directed to pharmaceutical particles comprisingganaxolone thereof aggregated with a complexing agent, the particlesexhibiting a ratio of D50 after incubation in SGF or SIF for 1-3 hoursto D50 prior to incubation of from about 1.5:1 to about 3:1; from about1.8:1 to about 2.7:1 or about 2:1 to about 1.5:1.

Certain embodiments of the invention are directed to the “uncured”ganaxolone complexes which are not tightly bound as evidenced byreduction of particle size by sonication. These embodiments are directedto pharmaceutical particles comprising ganaxolone thereof aggregatedwith a particle growth stabilizer, the particles exhibiting a ratio ofD50 after incubation in SGF or SIF for 1 hour at 37° C. and sonicationfor 1 minute to D50 prior to incubation of less than about 2:1, lessthan about 1.7:1, less than about 1.5:1 or less than about 1.4:1. Otherembodiments exhibit a ratio of D50 after incubation in SGF or SIF for 1hour and sonication for 1 minute to D50 prior to storage of from about1:2 to about 2:1, from about 1.3:1 to about 1.8:1 or from about 1.3:1 toless than about 1.5:1.

Certain embodiments of the invention are directed to the “cured”complexes which exhibit stable particle size. These embodiments aredirected to pharmaceutical particles comprising ganaxolone thereofcomplexed with a complexing agent, the particles cured for a sufficienttime until an endpoint is reached such that the D50 does not change bymore than about 5% as measured over 3 days after curing. In otherembodiments, the particles are cured for a sufficient time until anendpoint is reached such that the D50 does not change by more than about12%, more than about 10%, more than about 8% or more than 5% over 1month after the curing period.

In further embodiments, the particles are cured for a sufficient timeuntil an endpoint is reached such that the D50 does not change by morethan about 5% (over the instrument's variability at the measure particlesize) after 20 days after curing, 40 days after curing, 60 days aftercuring, or 80 days after curing storage conditions of 5° C. to 25° C.)

The endpoint needed to reach stable particles can be ascertained by oneskilled in the art. For example, the endpoint can be reached in about 5days to about 25 days; in about 5 days to about 7 days, in about 7 daysto about 14 days, in about 14 days to about 21 days, or about 10 days toabout 15 days.

In certain embodiments, the particles have a D50 prior to storage ofless than 350 nm, less than 250 nm or less than 150 nm. In otherembodiments, the particles have a D50 prior to storage of from about 50nm to about 350 nm, from about 75 nm to about 250 nm or from about 100nm to about 150 nm.

The formulation comprising the ganaxolone-complex particles can comprisethe complexes suspended in a dispersing agent (i.e., a suspension).

The addition of a complexing agent in the ganaxolone suspensionformulations was also found to reduce side effects of ganaxolone whileachieving adequate exposure. Without being bound by theory, it isbelieved that the lower side effect is achieved through larger overallparticle size distribution of the ganaxolone-preservative complexeswhile adequate exposure is achieved through larger surface area of thecomplex versus a single particle of the same size.

In certain embodiments, desirable formulations can be obtained by usingappropriate amounts of a complexing agent, a hydrophilic polymer such asHPMC and/or PVA and other components in ganaxolone suspensionformulations to achieve an optimal balance between maximumbioavailability and minimal side effects. An exemplary ganaxolonesuspension formulation comprises about 5 wt % ganaxolone, about 5 wt %HPMC, about 0.1 wt % SLS, about 0.1 wt % methylparaben, about 0.02 wt %propylparaben, 0.09% sodium citrate, 0.12% citric acid, 0.06% sodiumcitrate, 0.03% simethicone emulsion (30% in water) and about 1 wt % PVA,based on the total weight of the final suspension formulation.Additional ingredients such as flavoring agent and sweetener can beadded at appropriate levels to make theses formulations more palatable.Another exemplary formulation comprises the same composition asimmediately above except with HPMC levels reduced to 2.5%, and PVAremoved.

Ganaxolone suspensions comprising HPMC, SLS, methylparaben,propylparaben, and PVA was found to provide desirable pharmacokineticresults in animal studies. A composition without PVA gave higherexposure (2-fold) but also gave higher sedation scores in dogs. WhetherPVA is desirable or not in humans will depend on the relativetherapeutic ratios.

Cured ganaxolone particulate complexes are more desirable as thesecompositions will provide a more uniform result due to a decreasedchange in particle size over time, better thermal stability and lessaggregation in the gastrointestinal tract.

As discussed previously, ganaxolone has very low aqueous solubility. Onemethod of improving ganaxolone bioavailability is through the use ofsmaller ganaxolone particles (e.g., less than about 500 nm). However, anincrease in bioavailability will be expected to also result in anincrease in side effects (e.g., sedation). Cured formulations comprisingganaxolone-complexes having appropriate particle size (e.g. 200 to 350nm) can minimize side effects while maintaining adequate exposure. Forsolid dose forms of Ganaxolone where disintegration can be controlled byother techniques and with drugs without a sedative side effect, maximaldissolution and the smallest stable particle size will usually encompassthe most preferred embodiments. As will be demonstrated later, once thecuring period is complete, the material can be re-milled to obtainsmaller stable particles if desired.

It has also been found that formulations containing ganaxolone complexesreduce the variability in pharmacokinetic parameters between ganaxolonedosed in the fed and fasted states. Example T, below, demonstrates theeffect of preservative in ganaxolone particles on Cmax and AUC(0-τ).

In view of the unexpected effect of methylparaben and propylparaben onCmax and AUC(0-τ) of ganaxolone particles, the present invention isdirected to pharmaceutical compositions, wherein the ratio of thefasting Cmax provided by composition(s) with ganaxolone complexes withthose to the Cmax provided by the composition without the parabencomplexes is less than about 1:2; less than about 1.6 or less than about1:1. In certain embodiments, the ratio of the fasting AUC(0-τ) providedby the composition with a complexing agent to the AUC(0-τ) provided bythe composition without the complexing agent is less than 1.4:1; lessthan about 1.3:1 or less than about 1.2:1. In other embodiments, theratio of the fed Cmax provided by the stable composition with thecomplexing agent to the Cmax provided by the composition without thecomplexing agent is less than about 1:1.4; less than about 1:1.2 or lessthan about 1:1. The present invention is also directed to formulationscontaining stable ganaxolone compositions with complexing agents,wherein the ratio of the fed AUC(0-τ) to the fasted AUC(0-τ) provided bythe composition is from about 1.5:1 to about 5:1, from about 2:1 toabout 4:1, or from about 2.5:1 to about 3:1. In other aspects, the ratioof the fed Cmax to the fasted Cmax provided by the composition is fromabout 2:1 to about 7:1, from about 2.5:1 to about 5:1, or from about2.8:1 to about 3.8:1.

Xc. Vinyl Polymers as Pharmacokinetic Modifiers

The use of vinyl polymers (e.g., polyvinyl alcohol (PVA)) during orpost-milling appears to have little effect on post-milling particle sizeunder storage conditions at ambient temperature. However, data suggeststhat vinyl polymers do prevent flocculation of ganaxolone particles insimulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Thereduction in flocculation of ganaxolone particles in SGF and SIF isgreater in ganaxolone suspension formulations containing vinyl polymersand complexing agents. Once the curing period is over, the ganaxolonecomplex particles are stable and the added stabilization of PVA tosuppress agglomeration/flocculation is not observed.

The use of vinyl polymers was also found to reduce ganaxolone exposurelevels and reduce the exposure variability between the fed and fastedstate. The use of vinyl polymers in ganaxolone formulations (e.g., insuspensions) was further found to reduce the ratio of Cmax to AUC(0-τ).Data demonstrating the effect of vinyl polymers on the exposurevariability between the fed and fasted state and the ratio of Cmax toAUC(0-τ) is shown in Example 18, table 7, wherein PVA is exemplified.

The preferred vinyl polymer of the present invention is polyvinylalcohol. The amount of the vinyl polymer can be in an amount from about0.01% to about 5%, based on the total weight of the particles, or can bein an amount of from about 0.1% to about 2%, based on the total weightof the particles or from about 0.5% to about 1.5%, based on the totalweight of the liquid formulation.

In view of this unexpected effect of vinyl polymers on thepharmacokinetics of ganaxolone, certain embodiments of the presentinvention are directed to pharmaceutical compositions comprisingparticles comprising ganaxolone thereof and a vinyl polymer, theparticles having a D50 of less than about 500 nm. In certainembodiments, the particles have a D90 of less than about 500 nm.

The pharmaceutical compositions of the present invention containingganaxolone and a vinyl polymer can have the ratio of the fasting Cmaxprovided by the composition with the vinyl polymer to the Cmax providedby the composition without the vinyl polymer of less than about 0.75:1;less than about 0.60:1 or less than about 0.50:1.

In certain embodiments, the ratio of the fasting Cmax provided by thecomposition with the vinyl polymer to the Cmax provided by thecomposition without the vinyl polymer is more than about 0.20:1; morethan about 0.30:1 or more than about 0.40:1.

In other embodiments, the ratio of the fasting AUC(0-τ) provided by thecomposition with the vinyl polymer to the AUC(0-τ) provided by thecomposition without the vinyl polymer is less than about 0.8:1; lessthan about 0.70:1 or less than about 0.6:1.

The certain embodiments, the ratio of the fed Cmax provided by thecomposition with the vinyl polymer to the Cmax provided by thecomposition without the vinyl polymer is less than about 0.95:1; lessthan about 0.85:1 or less than about 0.75:1.

In other embodiments, the ratio of the fed Cmax provided by thecomposition with the vinyl polymer to the Cmax provided by thecomposition without the vinyl polymer is more than about 0.20:1; morethan about 0.30:1 or more than about 0.40:1.

In further embodiments, the ratio of the fed AUC(O-t) provided by thecomposition with the vinyl polymer to the AUC(O-t) provided by thecomposition without the vinyl polymer is less than about 0.9:1; lessthan about 0.80:1 or less than about 0.7:1.

In certain embodiments, the ratio of the fed AUC(0-τ) to the fastedAUC(0-τ) provided by the PVA composition is from about 1:1 to about 5:1,from about 1.5:1 to about 4:1, or from about 2:1 to about 3:1

In other embodiments, the ratio of the fed Cmax to the fasted Cmaxprovided by the PVA composition is from about 1.5:1 to about 2.5:1, fromabout 1.6:1 to about 2.4:1, or from about 1.8:1 to about 2.2:1.

The use of vinyl polymers with ganaxolone also results in reducedflocculation of the particles. In certain embodiments containing vinylpolymers, the D50 does not increase more than about 25%, not more thanabout 20% or not more than about 15% after 3 hours in SGF. In otherembodiments, the D50 does not increase more than about 25%, not morethan about 20% or not more than about 15% after 3 hours in SIF.

In embodiments containing ganaxolone and a vinyl polymer, the ganaxolonecan be complexed with ingredients such as parabens, organic acids,organic acid salts, aromatic acids and aromatic esters, inorganic acids,inorganic salts, pharmaceutically acceptable salts or a combinationthereof (see above).

In certain embodiments containing both vinyl polymers and at least onecomplexing agent, the D50 does not increase more than about 15%, notmore than about 12% or not more than about 8% after 1 hour in SGF. Inother embodiments, the D50 does not increase more than about 15%, notmore than about 10% or not more than about 8% after 1 hour in SIF.

A pharmaceutical composition comprising particles comprising ganaxolone,the particles having a D50 of less than 500 nm, the compositionproviding a ratio of fed AUC(0-τ) to fasted AUC(0-τ) in beagle dogs fromabout 1:1 to about 2.5:1, from about 1.2:1 to about 1.9:1, or from about1.4:1 to about 1.8:1.

While certain formulations have been exemplified which provideparticular pharmacokinetic parameters, certain embodiments of theinvention are directed to ganaxolone formulations which provideparticular pharmacokinetic profiles, regardless of the particularexcipients utilized in the formulation. The profiles include (i) a ratioof fed Cmax to fasted Cmax from about 1.5:1 to about 4:1, from about1.6:1 to about 3:1, or from about 1.8:1 to about 2.5:1, (ii) an AUC(0-24) from about 100 to about 375 ng*h/mL or from about 150 to about325 ng*h/mL for a 200 to a 500 mg ganaxolone administered to an adulthuman in the fasted state, (iii) a C_(max) from about 25 to about 85ng/mL for after a 200 to a 500 mg ganaxolone dose administered to anadult subject in the fasted state, (iv) an AUC (0-24) hours from about250 to about 1200 ng*h/mL or from about 400 to about 1000 ng*h/mL forafter a 200 to a 500 mg ganaxolone dose administered to an adult subjectin the fed state, and (v) a Cmax from about 60 to about 350 ng/mL orfrom about 80 to about 275 ng/mL after a 200 to a 500 mg ganaxolone doseadministered to an adult subject in the fed state.

XI. Milling with Simethicone as an Anti-Foaming Agent

Foaming during the nanosizing of pharmaceutical products can presentformulation issues and can have negative consequences for particle sizereduction. For example, high levels of foam or air bubbles in the millcan cause a drastic increase in viscosity rendering the milling processinoperable. Even a very low level of air presence can dramaticallyreduce milling efficiency causing the desired particle sizeunachievable. This may be due to the resultant air in the millcushioning the milling balls and limiting grinding efficiency. The airalso can form a microemulsion with the milled ingredients which presentsmany issues with respect to the delivery of an accurate dose andpalatability.

Simethicone is a known anti-foaming agent. However, simethicone is notwater soluble and therefore would be expected to interfere with alaser/light scattering particle size determination. Therefore,simethicone would not be expected to be a suitable anti-foaming agent tobe utilized in the particle reduction of pharmaceutical agents.

Regardless of this expectation, the present invention is directed to theobservation that simethicone is suitable to be used as an anti-foamingagent in the reduction of particle size of pharmaceutical products as itdoes not interfere with the measurement of the particles. This may bedue to simethicone being transparent to tungsten and laser light.

Simethicone can be added to the milling process, e.g., as a 30% emulsionsold by Dow Corning (Dow Corning 7-9245 or Dow Corning Q7-2587),however, any suitable percentage of simethicone in any suitableformulation can be utilized.

The amount of 30% simethicone emulsion utilized in the particlereduction procedures of the present invention can be any suitableamount, e.g., 500 ppm or less, or 350 ppm or 100 ppm or less, toeliminate or substantially eliminate the foam of the ganaxolone millingslurry, facilitating exclusion of air from the mill. One skilled in theart would be able to ascertain the amount of simethicone from differentpercentages of simethicone formulations

In view of the observation that simethicone is a suitable anti-foamingagent for use in particle reductions, certain embodiments of the presentinvention are directed to a method of milling pharmaceutical productscomprising incorporating a pharmaceutically active agent, a suitableamount of simethicone, milling beads and optional pharmaceuticallyacceptable excipients into a mill; and milling mixture for a suitabletime to obtain nanosized particles. In preferred embodiments, the activeagent is ganaxolone thereof. The optional pharmaceutically acceptableexcipients can be any of the excipients utilized in preparing smallparticles as disclosed herein.

The simethicone can be added as its pure liquid form (100%) or can bemixed with a suitable vehicle prior to incorporation into the millingprocess of the present invention. For example, the simethicone can beadded in the form of a diluted liquid, including not limited to,

a solution or an emulsion, or a suspension. The concentration ofsimethicone in the liquid can be from about 1% to about 99%; from about20% to about 80% or from about 20% to about 50%. Preferably, thesimethicone is in a 30% emulsion.

The amount of simethicone present in the milling slurry can be anysuitable amount which provides the intended benefits described above.Typical amount employed with good results ranges from 50-300 ppm.

In certain embodiments, the recovered ganaxolone particles contain atrace amount of simethicone in the final product. The final productcomprising ganaxolone particles may comprise from about 0.001% to about0.1% simethicone, or from about 0.005% to about 0.05% simethicone, basedon the totals weight of the composition.

The end product of the milling processes utilizing simethicone cancomprise the active agent particles suspended in a dispersing agent(i.e., a suspension).

XIb. Microprecipitating to Obtain Ganaxolone Dispersions ComprisingNanoparticles

Ganaxolone particles can also be prepared by homogeneous nucleation andprecipitation in the presence of a wetting agent or dispersing agent asdescribed in U.S. Pat. No. 5,560,932 and U.S. Pat. No. 5,665,331, whichare specifically incorporated by reference. Such ganaxolone particlesare stable and do not show and appreciable increase in effectiveparticle size over time. This is a method of preparing stabledispersions of ganaxolone in the presence of one or more dispersing orwetting agents and one or more colloid stability enhancing surfaceactive agents. Such a method comprises, for example: (1) dispersingganaxolone in a suitable liquid media; (2) adding the mixture from step(1) to a mixture comprising at least on dispersing agent or wettingagent such that at the appropriate temperature, the ganaxolone isdissolved; and (3) precipitating the formulation from step (2) using anappropriate anti-solvent (e.g., water). The method can be followed byremoval of any formed salt, if present, by dialysis or filtration andconcentration of the dispersion by conventional means. In oneembodiment, the ganaxolone particles are present in an essentially pureform and dispersed in a suitable liquid dispersion media. A preferredliquid dispersion medium is water. However, other liquid media can beused including, for example, aqueous salt solutions, oils (e.g.,safflower, olive or cremephor), and solvents such as ethanol, t-butanol,hexane, and glycol. The pH of the aqueous dispersion media can beadjusted by techniques known in the art. In this embodiment, theganaxolone particles comprise a discrete phase having been admixed witha dispersing agent or wetting agent. Useful dispersing agents or wettingagents are experimentally determined, but effectively minimize thedifference in lipophilicity of ganaxolone and the dispersion media byinducing a non-covalent ordered complex between the media, the wettingagent, and ganaxolone.

XIc. Homogenization to Obtain Ganaxolone Dispersions ComprisingNanoparticles

In yet another embodiment, the ganaxolone particles described herein areproduced by high pressure homogenization (see generally U.S. Pat. No.5,510,118). Such a method comprises dispersing ganaxolone particles in aliquid dispersion medium, followed by subjecting the dispersion torepeated homogenization to reduce the particle size of the ganaxolone tothe desired effective average particle size. The ganaxolone particlescan be reduced in size in the presence of at least one or moredispersing agents or wetting agents. Alternatively, the ganaxoloneparticles can be contacted with one or more dispersing agents or wettingagents either before or after attrition. Other compounds, such as adiluent, can be added to the ganaxolone/dispersing agent compositionbefore, during, or after the size reduction process. In one embodiment,unprocessed ganaxolone can then be added to a liquid medium in which itis essentially insoluble to form a premix. The concentration of theganaxolone in the liquid medium can vary from about 0.1-60% w/w, andpreferably is from 5-30% (w/w). It is preferred, but not essential, thatthe dispersing agents or wetting agents be present in the premix. Theconcentration of the dispersing agents or wetting agents can vary fromabout 0.1 to 90%, and preferably is 1-75%, more preferably 20-60%, byweight based on the total combined weight of the ganaxolone anddispersing agents or wetting agents. The apparent viscosity of thepremix suspension is preferably less than about 1000 centipoise. Thepremix then can be transferred to the microfluidizer and circulatedcontinuously first at low pressures, then at maximum capacity having afluid pressure of from about 3,000 to 30,000 psi until the desiredparticle size reduction is achieved. The particles must be reduced insize at a temperature which does not significantly degrade the drugsubstance or cause significant particle size growth throughsolubilization. Next, one of two methods can be used to collect theslurry and re-pass it in a microfluidizer. The “discreet pass” methodcollects every pass through the microfluidizer until all of the slurryhas been passed through before re-introducing it again to themicrofluidizer. This guarantees that every substance or particle has“seen” the interaction chamber the same amount of times. The secondmethod re-circulates the slurry by collecting it in a receiving tank andallowing the entire mixture to randomly mix and pass through theinteraction chamber.

Dispersing agents and/or wetting agents, if not present in the premix,can be added to the dispersion after attrition in an amount as describedfor the premix above. Thereafter, the dispersion can be mixed, e.g., byshaking vigorously. Optionally, the dispersion can be subjected to asonication step, e.g., using an ultrasonic power supply. For example,the dispersion can be subjected to ultrasonic energy having a frequencyof 20-80 kHz for a time of about 1 to 120 seconds.

The relative amount of ganaxolone and dispersing agents and/or wettingagents can vary widely. The dispersing agents and/or wetting agentspreferably are present in an amount of about 0.1-10 mg per square metersurface area of ganaxolone. The dispersing agents or wetting agents canbe present in an amount of 0.1-90%, preferably 5-50% by weight based onthe total weight of the dry ganaxolone particles during the particlesize reduction.

The resulting ganaxolone dispersion is stable and consists of the liquiddispersion medium and the above-described particles. The dispersion ofganaxolone particles can be spray coated onto sugar spheres or beads oronto a pharmaceutical excipient in a fluid-bed spray coater bytechniques well known in the art.

XId. Fluid Bed Spray-Granulation to Obtain Amorphous GanaxoloneCompositions

In still another embodiment, the ganaxolone particles described hereinare produced by spraying-drying or by spray-drying into a fluid bed.Such a method comprises spraying a mixture of ganaxolone and at leastone solubility enhancer and/or wetting agent and/or viscosity enhancingagent and optionally a crystallization inhibitor compound in solventcomprised of one or more organic solvents or a mixture of water and oneor more alcohols, under conditions that allow the solvent to be removedfrom said mixture fast enough in the case of a fluidized bed to depositamorphous or semi-amorphous material onto a carrier bead or in the caseof direct spray drying onto the excipients mixture producing a powder.

In one embodiment, the process generally carried out by a) introducing acarrier excipient in the form of a dry powder, spray granules ormicrogranules into a fluidized bed drier in which the bed is kept atfrom about 40° C. to about 200° C., preferably about 50° C. to about100° C.; b) spraying onto the fluidized bed of excipient apharmaceutically acceptable alcohol (e.g., ethanol, n-butanol, methanol,and mixtures thereof) or organic solvent (acetone, ethyl acetate,toluene) solution comprising ganaxolone and at least one solubilityenhancer (e.g. Cholesterol, Vitamin E TPGS, Cremophor and a crystalinhibitor (e.g. Povidone K-12, Hydroxypropylmethylcellulose acetatestearate (HPMCAS) and a binder (lactose, sucrose, starch) which canbecome amorphous upon spray drying such that stable particles ofganaxolone solution exist in a mixture with the carrier excipient,wherein said stable particles of ganaxolone are amorphous or acombination of amorphous and crystalline material with broad particlesize range from 200 nm to 2 microns. The resulting ganaxolone particlesare stable and maintain increased kinetic dissolution properties asdetermined by standard dissolution methods (in vitro) over a 1 yearperiod at 25° C. in a solid dosage form. The ganaxolone containingmixture can be further processed into a solid dosage form or packagedfor reconstitution into an aqueous dispersion.

In another embodiment, the process is carried out by a) introducing acarrier excipient in the form of a dry powder, spray granules ormicrogranules into a fluidized bed drier in which the bed is kept atfrom about 50° to about 200° C., preferably about 50° to about 100° C.;b) spraying onto the fluidized bed of excipient a water-containingmixture of ganaxolone and at least one solubility enhancer, a crystalinhibitor, and a dispersing agent such that stable particles containingganaxolone exist in a mixture with the excipient, wherein said stableparticles of ganaxolone have an effective particle size of about 500 nmto about 1 μm. The resulting ganaxolone particles are stable and do notappreciably increase in effective particle size over time

The carrier excipient is preferably a highly water-soluble compound orpolymer. The resulting mixture of water soluble carrier excipient, suchas a sugar or sugar alcohol, and ganaxolone is advantageous because thecarrier excipients can disperse into water, thereby increasing thedissolution rate of ganaxolone particles in aqueous media.

Useful carrier excipients that can be employed in the fluidized bed forpharmaceutical compositions include, but are not limited to,saccharides, such as sugars and sugar alcohols (for example, lactose orsucrose, mannitol, or sorbitol), starches, flour, cellulose preparationsand/or salts such as carbonates, bicarbonates and phosphates, forexample, tricalcium phosphate or calcium hydrogen phosphate.

Sugars and sugar alcohols used as a carrier excipient include sugar orsugar alcohols having a molecular weight of less than 500 daltons, andcapable of easily dispersing and dissolving in water, thereby improvingdissolution rate of ganaxolone. Examples of sugars and sugar alcoholsusable in the present invention include xylitol, mannitol, sorbitol,arabinose, ribose, xylose, glucose, mannose, galactose, sucrose,lactose, and the like. They can be used alone, or as a mixture of two ormore of these compounds. In one embodiment, the sugars are sucrose ormannitol.

Useful solubility enhancers, other than organic solvents, that can beemployed in the fluidized bed for pharmaceutical compositions include,but are not limited to, propylene glycol, PEG having a molecular weightgreater than 400 daltons, cholesterol, letichin, cremophor, Vitamin ETPGS, triacetin, olive oil and castor oil.

Useful crystal inhibitors that can be employed with spray drying forpharmaceutical compositions include, but are not limited to,hydroxypropylmethylcellulose acetate stearate, polyvinylpyrrolidones(e.g., povidone K-12), and propylene glycol.

The ganaxolone particles generated by any of the methods describedherein can be utilized in solid or aqueous liquid dosage formulations,such as controlled release formulations, pulsatile dosage forms,multiparticulate dosage forms, solid dose fast melt formulations,lyophilized formulations, tablets, capsules, aqueous dispersions, oraerosol formulations.

XII. Methods of Making Small Particle Ganaxolone Formulations

Small particle ganaxolone formulations can be manufactured using themethods described in, for example, in U.S. Pat. Nos. 4,783,484,4,826,689, 4,997,454, 5,741,522 and 5,776,496, each of which isspecifically incorporated by reference.

Such methods include: (1) forming a solution of ganaxolone in a suitableorganic solvent. This can occur as the ganaxolone is synthesized as adissolved solid, or it can be done by simply dissolving particles ofganaxolone in the solvent of choice. Any solvent that is miscible inwater is satisfactory, and includes for example, dimethylacetamide(DMA), dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). (2)diluting the solution with a non-solvent that does not cause ganaxoloneto precipitate. The non-solvent causes greater dispersion of thedissolved molecules of ganaxolone in the liquid phase. Greater dilutionof the solution with non-solvent produces larger particles, and lessdilution of the solution with non-solvent produces smaller particles.The non-solvent should not precipitate the ganaxolone when it is addedto the solution. Non-solvents in which the compound is slightly moresoluble than in water are preferred, for example, include loweraliphatic alcohols, such as ethanol. Also, proportions of non-solvent tosolvent at a ratio of 2 or more can produce 1 to 3 micron sizedparticles (depending on other parameters); and ratios of less than 2produce submicron particles, at least as applied to DMSO solutionsdiluted with ethanol. (3) To precipitate the ganaxolone from thesolution in a desired particle size, an aqueous solution of a surfactantand or soluble binders and dispersing agents is prepared in sufficientquantity to effect complete precipitation of the ganaxolone and tostabilize the resulting suspension of particles against aggregation. Thesurfactant provides the stabilization against aggregation, and the wateris the precipitating agent. Presence of extra surfactant is advisable toensure stabilization so that precipitated particles suspended in liquiddo not aggregate, forming particles of an improperly large size.Surfactants are chosen for their compatibility with the compound andtheir ability to stabilize a suspension of ganaxolone particles. Forexample, a solution of 5% C-30 or 0.1% C-15 polyvinylpyrrolidone (PVP)in water is preferred; but 5% Pluronic F-68, 0.33% gelatin, 0.33%gelatin plus 0.6% Hetastarch, 0.33% gelatin plus 0.002% propyleneglycol, 2% polyvinylpyrrolidone/vinyl acetate copolymer, and 0.33%gelatin plus 2% sucrose can also be used. Another embodiment uses 5%HPMC (Pharmacoat 603), 0.3% SLS and 1% PVA. To precipitate ganaxoloneparticles in the desired sizes, the aqueous solution and the organicsolution are combined under controlled conditions of temperature, ratioof infusion rate to stirring rate, and the proportion of non-solvent tosolvent in the dispersed solution. The precipitation of ganaxoloneoccurs exothermically, heating the organic solution and resultingsuspension. The temperature of the solution and resulting suspension iscontrolled to achieve the particle size of precipitate that is desired.Higher solution temperatures during precipitation produce largerparticles, and lower solution temperatures during precipitation producesmaller particles. Also, faster infusion rates at constant stirring rateof organic solution produce smaller particles, and slower infusion ratesproduce larger particles. (4) When the precipitation is complete, extraaqueous surfactant solution can be added to stabilize the suspendedganaxolone particles against agglomeration. The extra solution can beadded at a rapid rate, since all the ganaxolone is now precipitated inuniform sized particles. The precipitated particles are promptlyseparated from the organic solvents to prevent re-dissolving andre-precipitation of particles at undesirable sizes. Centrifuging is thepreferred way to do this. Promptly after separating the particles fromthe organic liquid, the particles are washed or rinsed with normalsaline solution to remove solvent and excess surfactant.

The ganaxolone particles generated by the methods described herein canbe utilized in solid or aqueous liquid dosage formulations, such ascontrolled release formulations, solid dose fast melt formulations,lyophilized formulations, tablets, capsules, aqueous dispersions, oraerosol formulations.

XIII. Other Formulations Utilizing Small Particles of Ganaxolone

In certain embodiments, the present invention is directed to apharmaceutical composition comprising particles comprising (i)ganaxolone thereof, (ii) a cellulosic polymer and (iii) sodium laurylsulfate; wherein 90% of the particles by weight have an effectiveparticle size of less than about 500 nm. Another embodiment comprises(i), (ii), (iii) and (iv) a complexing agent. In other embodiments, theparticles comprising (i), (ii) and (iii) above, and (i), (ii), (iii) and(iv) can have any effective particle size, range, or any othercharacteristic (e.g., pharmacokinetic profile) as disclosed herein.Additionally an ionic dispersion modulator and a water soluble spacercan be added. These formulations can also contain a polymer selectedfrom the group consisting of polyvinylpyrrolidone, polysaccharides,copolymers of vinyl acetate and vinyl pyrrolidone, polyvinyl alcohol,copolymers of vinyl acetate and vinyl alcohol, carboxymethylcelluloseand mixtures thereof.

In certain embodiments, the cellulosic polymer of (ii) ishydroxypropylmethylcellulose (Pharmacoat 603).

In certain embodiments, the present invention is directed to apharmaceutical composition comprising particles comprising (i)ganaxolone thereof, (ii) a polymer selected from the group consisting ofpolyvinylpyrrolidone, polysaccharides, copolymers of vinyl acetate andvinyl pyrrolidone, polyvinyl alcohol, copolymers of vinyl acetate andvinyl alcohol, carboxyalkylcelluloses, and mixtures thereof, and (iii) amaterial selected from the group consisting of sodium lauryl sulfate anddioctyl sodium sulfosuccinate, wherein 90% of the particles by weighthave an effective particle size of less than about 500 nm. In otherembodiments, the particles comprising (i), (ii) and (iii) above, canhave any effective particle size, range, or any other characteristic(e.g., pharmacokinetic profile) as disclosed herein. These formulationscan also contain a cellulosic polymer.

In certain embodiments, the polymer of (ii) is a copolymer of vinylacetate and vinyl pyrrolidone.

In certain embodiments, the ionic dispersion modulator is an organic orinorganic salt which does not contain a sulfonic acid or sulfonicacid/inorganic salt counterion group at the end of an alkyl chaincontaining more than one saturated carbon atom bonded to the carbon atombearing the sulfonic acid moiety.

In certain embodiments, the water soluble spacer is a saccharide orinorganic salt which do not contain a sulfonic acid or sulfonicacid/inorganic salt counterion group at the end of an alkyl chaincontaining more than one saturated carbon atom bonded to the carbon atombearing the sulfonic acid moiety.

The formulations of the present invention can also include a complexingagent including but are not limited to parabens, organic acids, organicacid salts, aromatic acids and aromatic esters inorganic acids,inorganic salts, and combinations thereof. Complexing agents do notcontain a sulfonic acid or sulfonic acid/inorganic salt counterion groupat the end of an alkyl chain containing more than one saturated carbonatom bonded to the carbon atom bearing the sulfonic acid moiety.

The formulations of the present invention can also include preservativesincluding but are not limited to parabens, organic acids, organic acidsalts, aromatic acids, aromatic esters, inorganic acids, inorganicsalts, pharmaceutically acceptable salts and combinations thereof.

Wetting agents such as sodium lauryl sulfate also do not appear toaffect the post milling particle size under storage conditions atambient temperature. However, addition of wetting agents during themilling process does improve the processing properties such as reductionof back pressure and more efficient grinding by reducing the overallviscosity of the milling slurry.

An anti-foaming agent can also be added to improve the milling process.For example, presence of simethicone (e.g., at 0.01% level) during themilling process Did not alter characterization of the formulation andgreatly improved the efficiency and reliability of the milling process.The addition of simethicone also produces a final aqueous formulationthat will foam less and provide more accurate dosing for the patient. Incertain embodiments, the ranges of ganaxolone, HPMC, PVA, SLS, parabens,benzoic acid/sodium benzoate and simethicone in the milling and thefinal suspension formulations are given in TABLE 1 as a weight percent(wt %) based on the total weight of the respective compositions.

TABLE 1 Milling Compositional Formulation Compositional Component Range,wt % to total weight Range, wt % to total weight GNX 10 to 30  3 to 20Or 15 to 27 Or 4 to 10 Or 10 to 25 Or 4 to 6 HPMC  2 to 10  2 to 10 Or 2to 6 Or 2 to 6 PVA 0 to 5 0 to 5 Or 0.5 to 2.5 0.5 to 2.5 SLS 0 to 1 0to 1 Or 0.1 to 0.5 0.1 to 0.5 Simethicone, 0 to 1 0 to 1 100% or Or 0 to0.04 Or 0 to 0.04 3x levels if 30% emulsion used Methylparaben   0 to0.25 0 to 0.25 Or 0 to 0.1 Or 0 to 0.1% Propylparaben   0 to 0.25   0 to0.25 Or 0 to 0.04 Or 0 to 0.04 Sodium   0 to 0.2   0 to 0.2 Benzoate/Benzoic acid

The particles disclosed above can be prepared according to any of themethods disclosed herein or by the methods described in U.S. Pat. No.6,375,986; 6,428,814; 6,432,381; 6,592,903; 6,908,626; or 6,969,529; thedisclosures of which are hereby incorporated by reference.

In certain embodiments, the invention is directed to a pharmaceuticalcomposition comprising particles comprising (i) ganaxolone thereof, (ii)a polymer selected from the group consisting of polyvinylpyrrolidone,polysaccharides, copolymers of vinyl acetate and vinyl pyrrolidone,polyvinyl alcohol, copolymers of vinyl acetate and vinyl alcohol,carboxyalkylcelluloses, cellulosic polymers and mixtures thereof, and(iii) a material selected from the group consisting of sodium laurylsulfate and dioctyl sodium sulfosuccinate (DOSS) and (iv) an ionicdispersion modulator and (v) a water soluble spacer, wherein 90% of theparticles by weight have an effective particle size of less than about500 nm (or any effective particle size, range, or any othercharacteristic as disclosed herein), wherein the composition comprises(a) an immediate release component comprising a first portion of theparticles and providing an immediate release of the ganaxolone orpharmaceutically acceptable salt thereof; and (b) a controlled releasecomponent comprising a second portion of the particles and providing acontrolled release of the ganaxolone or pharmaceutically acceptable saltthereof.

In certain embodiments, the controlled release component provides arelease selected from the group consisting of sustained release ordelayed release.

In certain embodiments, the controlled release component comprises acoating comprising a hydrophobic material, coated on the second portionof particles.

In certain embodiments, the controlled release component comprises amatrix comprising the second portion of particles dispersed in ahydrophobic material.

In certain embodiments, the immediate release component and thecontrolled release component are independently selected from the groupconsisting of a tablet, a pill, multiparticulates, a powder, a capsule,a solid dispersion, a solid solution, a pellet, or a granule.

In certain embodiments, the hydrophobic material is selected from thegroup consisting of an acrylic polymer, a cellulosic polymer, shellac,zein, fatty alcohols, hydrogenated fats, fatty acid esters, fatty acidglycerides, hydrocarbons, waxes, stearic acid, stearyl alcohol, andmixtures thereof.

In certain embodiments, the hydrophobic material is an enteric polymer.

In certain embodiments, the enteric polymer is selected from the groupconsisting of shellac, acrylic polymers, cellulose derivatives,polyvinyl acetate phthalate and mixtures thereof.

In certain embodiments, the delayed release component provides a dose ofthe ganaxolone or pharmaceutically acceptable salt thereof delayed byfrom about 2 hours to about 12 hours after administration.

In certain embodiments, the delayed release component provides a dose ofthe ganaxolone or pharmaceutically acceptable salt thereof delayed byfrom about 2 hours to about 8 hours after administration.

In certain embodiments, the delayed component provides a dose of theganaxolone or pharmaceutically acceptable salt thereof delayed by fromabout 3 hours to about 7 hours after administration.

In certain embodiments, the controlled release component provides asustained release of the ganaxolone or pharmaceutically acceptable saltthereof for about 2 hours to about 6 hours after administration.

In certain embodiments, the controlled release component provides asustained release of the ganaxolone or pharmaceutically acceptable saltthereof for about 3 hours to about 10 hours after administration.

In certain embodiments, the coating further comprises a plasticizer, acolorant, a detackifier, a surfactant, an anti-foaming agent, alubricant or a mixture thereof.

In certain embodiments, the immediate release component and thecontrolled release component independently comprise one or morepharmaceutically acceptable additives from the group consisting ofcarriers, binders, filling agents, suspending agents, flavoring agents,sweetening agents, disintegrating agents, dispersing agents,surfactants, lubricants, colorants, diluents, solubilizers, moisteningagents, plasticizers, stabilizers, penetration enhancers, wettingagents, anti-foaming agents, antioxidants, preservatives, or one or morecombinations thereof.

The pharmaceutical dosage forms disclosed herein having an immediaterelease component and a controlled release component in this section(XIII) can provide any pharmacokinetic profile as disclosed herein.

The dosage forms can be prepared according to any of the methodsdisclosed herein or by the methods described in U.S. Pat. Nos.5,209,746; 5,213,808; 5,221,278; 5,260,068; 5,260,069; 5,308,348;5,312,390; 5,318,588; 5,340,590; 5,391,381; 5,456,679; 5,472,708;5,508,040; 5,840,329; 5,980,508; 6,214,379; 6,228,398; 6,248,363;6,514,518; 6,569,463; 6,607,751; 6,627,223; 6,730,325; 6,793,936;6,902,742 and 6,923,988, the disclosures of which are herebyincorporated by reference.

XII. Methods of Use of Ganaxolone Formulations

The ganaxolone formulations described herein can be administered intherapeutically effective amounts for the treatment of a subject thathas had or is anticipating a convulsive state including, but not limitedto, status epilepticus, epileptic seizures or spasms. Specific types ofepileptic seizures include, but are not limited to, tonic-clonic (GrandMal), partial (Focal) seizures, catamenial seizures, acute repetitiveseizure, psychomotor (complex partial) seizures, absence (Petit Mal)seizure, and myoclonic seizures.

The ganaxolone formulations described herein can also be used for thetreatment of Infantile Spasms (IS). Infantile Spasm is a specific typeof seizure seen in an epilepsy syndrome of infancy and early childhoodknown as West Syndrome. The onset is predominantly in the first year oflife, typically between 3-6 months. The typical pattern of IS is asudden bending forward and stiffening of the body, arms, and legs;although there can also be arching of the torso. Spasms tend to beginsoon after arousal from sleep. Individual spasms typically last for 1 to5 seconds and occur in clusters, ranging from 2 to 100 spasms at a time.Infants may have dozens of clusters and several hundred spasms per day.Infantile spasms usually stop by age 5, but are often replaced by otherseizure types. West Syndrome is characterized by infantile spasms,abnormal and chaotic brain wave patterns, and mental retardation.

Additional conditions where the ganaxolone small particle formulationsdescribed herein can be used to treat include, but are not limited to,anxiety, stress, panic, depression and depression related disorders(e.g., post-partum depression), insomnia, premenstrual syndrome, PostTraumatic Stress Disorder (PTSD), substance abuse withdrawal (e.g.alcohol, benzodiazepine, barbiturate and cocaine), and hypertension. Theganaxolone formulations described herein can also be used in thetreatment of pain, migraine headaches and headaches (including migraine)associated with the pre and peri-menstrual period.

Other conditions diseases which the ganaxolone formulations describedherein can be used to treat include sphingolipid storage diseases, suchas Neimann Pick Type-C(NPC) and Mucolipidosis Type IV (ML-IV) lipidaccumulation.

Additionally, the ganaxolone formulations described herein can be usedfor the treatment of neurodegenerative diseases including, but notlimited to, AIDS-associated dementia, Alzheimer's disease, Huntington'sdisease, and Parkinson's disease diseases.

Actual dosage levels of the ganaxolone formulations described herein maybe varied to obtain an amount of active ingredient that is effective toobtain a desired therapeutic response for a particular composition andmethod of administration. The selected dosage level therefore dependsupon the desired therapeutic effect, on the route of administration, onthe desired duration of treatment, and other factors. However, oneaspect of the formulations and compositions described herein is toprovide ganaxolone formulations that comprise therapeutically effectiveamounts of ganaxolone such that the ganaxolone blood plasma levels beingmaintained at steady state are from about 10 ng/ml to about 100 ng/ml(C_(min)) upon administration. In one embodiment, the ganaxoloneformulations described herein can be used for the treatment of InfantileSpasms or an epilepsy related disorder wherein the formulation providesa therapeutically effective amount of ganaxolone (C_(min)) of about 25to 50 ng/ml of ganaxolone in the blood plasma at steady state. Inanother embodiment, the ganaxolone formulations described herein can beused for the treatment of a non-epilepsy related disorder wherein theformulation provides a therapeutically effective amount of ganaxolone(C_(min)) of about 15 to 30 ng/ml of ganaxolone in the blood plasma atsteady state.

XIII. Pharmacokinetic Analysis

Any standard pharmacokinetic protocol can be used to determine bloodplasma concentration profile in humans following administration of aganaxolone formulation described herein, and thereby establish whetherthat formulation meets the pharmacokinetic criteria set out herein. Forexample, a randomized single dose crossover study can be performed usinga group of healthy adult human subjects. The number of subjects shouldbe sufficient to provide adequate control of variation in a statisticalanalysis, and is typically about 10 or greater, although for certainpurposes a smaller group can suffice. Each subject receivesadministration at time zero a single dose (e.g., 300 mg) of a testformulation of ganaxolone, normally at around 8 am following anovernight fast. The subjects continue to fast and remain in an uprightposition for about 4 hours after administration of the ganaxoloneformulation. Blood samples are collected from each subject prior toadministration (e.g., 15 minutes) and at several intervals afteradministration. For the present purpose it is preferred to take severalsamples within the first hour and to sample less frequently thereafter.Illustratively, blood samples could be collected at 15, 30, 60 and 120minutes after administration, and then every hour from 2 to 10 hoursafter administration. Additional blood samples may also be taken later,for example at 12 and 24 hours after administration. If the samesubjects are to be used for study of a second test formulation, a periodof at least 7 days should elapse before administration of the secondformulation. Plasma is separated from the blood samples bycentrifugation and the separated plasma is analyzed for ganaxolone by avalidated high performance liquid chromatography/tandem weightspectrometry (LC/APCI-MS/MS) procedure such as, for example, Ramu etal., Journal of Chromatography B, 751 (2001) 49-59).

Plasma concentrations of ganaxolone referenced herein are intended tomean total ganaxolone concentrations including both free and boundganaxolone. Any formulation giving the desired pharmacokinetic profileis suitable for administration according to the present methods.Exemplary types of formulations giving such profiles are liquiddispersions and solid dose forms of the ganaxolone formulation describedherein. Aqueous dispersions of ganaxolone are stable at temperaturesfrom 4° C. up to 40° C. for at least 3 months.

EXAMPLES

This invention is further illustrated by the following examples thatshould not be construed as limiting. Those of skill in the art ofpharmaceutical formulation will readily appreciate that certainmodifications to the examples described herein may be needed,particularly for changes in formulation batch size. Any methods,materials, or excipients which are not particularly described will begenerally known and available those skilled in the drug design and assayand pharmacokinetic analysis. The particle size data, for examples inwhich a ganaxolone particle size is reported, were obtained using aHoriba LA-910 Laser Light Scattering Particle Size analyzer (HoribaInstruments, Irvine, Calif.) and reported as volume weighted median(D50). Studies of ganaxolone particles in liquids, beads, powders andimmediate release dosage forms in SGF and SIF are performed bydispersing an appropriate amount of the ganaxolone formulation into 20mL of SGF or SIF in a vial to obtain a measuring concentration ofganaxolone of about 0.5 mg/mL. For example, in one embodiment, 200 mg ofa ganaxolone suspension formulation containing 5 wt % of ganaxolone andappropriate levels of HPMC, PVA, SLS, and preservatives was dispersedinto 20 mL of SGF or SIF in a vial for measurement. The vial is immersedin an oil bath kept at 36 to 38° C. for 3 h. The sample is assessedvisually for signs of flocculation and particle size is measured on aHoriba LA-910 to obtain D50 values.

ABBREVIATIONS

The following abbreviations are used in the examples below. Otherabbreviations used in the examples will be understood by those of skillin the art of pharmaceutical formulations.

GNX Ganaxolone HDPE High Density Polyethylene HPMCHydroxypropylmethylcellulose PVA Polyvinyl alcohol SLS Sodium LaurylSulfate DOSS Sodium docusate SGF Simulated gastric fluid SIF Simulatedintestinal fluid WT Weight

Example 1

The purpose of this example is to describe the preparation of an aqueousdispersion of ganaxolone comprising particles having an effectiveparticle size of less than 500 nm.

Crystalline ganaxolone is premixed with polyvinylpyrrollidinone/vinylacetate (S-630), and sodium lauryl sulfate at concentrations of 30%,10%, and 0.1% (weight/weight of milling slurry) in deionized water,respectively, and milled under high energy milling conditions (Dyne-Mill(Willy Bachofen AG)) water jacketed with a grinding media consisting ofZrO₂ having a size ranging 0.4 to 0.6 mm. The crystalline ganaxolone ismilled with the grinding media for a total of 1 hour. The millingtemperature is not allowed to exceed 50° C. The milling concentration isabout 30% ganaxolone by weight vs. the milling media. The milling mediacontains about 10% weight/volume of the PVP/VA(S-630) and 0.1% SLS. Theresulting blended ganaxolone dispersion is separated from the grindingmedia by filtration through a 5 micron filter to yield a ganaxolonedispersion which can then be evaluated for performance in animalpharmacokinetics. Liquid aqueous dispersions are formulated by dilutingthe milled dispersion with deionized water to a final concentration of50 mg/ml after the addition of sucrose, methyl and propylparaben andartificial strawberry flavoring (0.005% volume/volume).

Example 2

The purpose of this example is to describe the preparation of an aqueousdispersion of ganaxolone comprising particles having an effectiveparticle size of about 150 nm.

Crystalline ganaxolone is premixed with polyvinylpyrrollidinone/vinylacetate (S-630), and dioctyl sodium sulfosuccinate at concentrations of30%, 2.5%, and 0.05% (weight/weight) in deionized water, respectively,and milled under high energy milling conditions (Dyne-Mill (WillyBachofen AG)) water jacketed with a grinding media consisting ofzirconium oxide beads having a size ranging 0.1 to 0.2 mm. Thecrystalline ganaxolone is milled with the grinding media for a total of1 hour. The milling temperature is not allowed to exceed 50° C. Themilling concentration is about 30% ganaxolone by weight vs. the millingmedia. The milling media contains about 10% weight/weight of thePVP/VA(S-630) and 0.05% DOSS (weight/weight) and deionized water. Theresulting blended ganaxolone dispersion is separated from the grindingmedia by filtration through a 5 micron to yield a ganaxolone dispersionwhich can then be evaluated for performance in animal pharmacokinetics.Liquid aqueous dispersions are formulated by diluting the milleddispersion with deionized water to a final concentration of 50 mg/mlafter the addition of sucrose, methyl and propylparaben and artificialstrawberry flavoring (0.01% volume/volume).

Example 3

The purpose of this example is to describe the preparation of an aqueousdispersion of ganaxolone comprising particles having an effectiveparticle size of about 150 nm.

Crystalline ganaxolone is premixed with hydroxypropylmethylcellulose,and DOSS at concentrations of 25%, 10%, and 0.3% (weight/weight) indeionized water, respectively (in alternative methods, the HPMC can bein a range from about 0.5% to 5% or 1.5% to 3%), and milled under highenergy milling conditions (Dyno®-Mill (Willy Bachofen AG)) waterjacketed with a grinding media consisting of zirconium oxide beadshaving a size ranging 0.1 to 0.2 mm. The crystalline ganaxolone ismilled with the grinding media for a total of 1 hour. The millingtemperature is not allowed to exceed 50° C. The milling concentration isabout 25% ganaxolone by weight vs. the grinding media. The grindingmedia consists of 0.1 to 0.2 mm ZrO₂ beads filling 85% of the grindingvessel volume (volume/volume). The resulting blended ganaxolonedispersion is separated from the grinding media by filtration through a5 micron filter to yield a ganaxolone dispersion which can then beevaluated for performance in animal pharmacokinetics. Liquid aqueousdispersions are formulated by diluting the milled dispersion withdeionized water Containing 2% HPMC and 0.1% SLS (Weight/Weight) to afinal concentration of 20 mg/ml for animal testing. A suitabledispersion for human use would require the addition of sucrose, methyland propylparaben and artificial strawberry flavoring (0.005%volume/volume).

Example 4

The purpose of this example is to describe the preparation of an aqueousdispersion of ganaxolone comprising particles having an effectiveparticle size of about 100 nm.

Crystalline ganaxolone is premixed with hydroxypropylmethylcellulose,and sodium lauryl sulfate at concentrations of 25%, 2%, and 0.1%(weight/weight) in deionized water, respectively (in alternativemethods, the HPMC can be in a range from about 0.5% to 10% or 1.5% to3%), and milled under high energy milling conditions (Dyno®-Mill (WillyBachofen AG)) water jacketed with a grinding media consisting ofzirconium oxide beads having a size ranging 0.1 to 0.2 mm. Thecrystalline ganaxolone is milled with the grinding media for a total of2 hours at 15 meters/sec ejection velocity. The milling temperature isnot allowed to exceed 50° C. The milling concentration is about 25%ganaxolone by weight vs. the milling media. The milling media containsabout 2% weight/weight of the HPMC and 0.1% SLS (w/w) in deionizedwater. The resulting blended ganaxolone dispersion is separated from thegrinding media by filtration through a 5 micron filter to yield aganaxolone dispersion which can then be evaluated for performance inanimal pharmacokinetics by diluting with distilled water containing 2%HPMC and 2.5% sucrose (w/w) to a final concentration of 20 mg/ml).

Example 5

In Example 5, ganaxolone particles with an effective particles sizeunder 500 nm were obtained utilizing the parameters of Example 1utilizing 30% ganaxolone, 10% polyvinylpyrrollidinone/vinyl acetate,0.3% DOSS, 0.1 to 0.2 mm ZrO₂ beads at 85% volume with a millingresidence time of about 30 minutes.

Example 6

In Example 6, ganaxolone particles with an effective particles sizeunder 500 nm were obtained utilizing the parameters of Example 1utilizing 30% ganaxolone, 10% HPMC, 0.3% DOSS, 0.1 to 0.2 mm ZrO₂ beadsat 85% volume with a milling residence time of about 30 minutes.

Example 7

In Example 7, ganaxolone particles with an effective particles sizeunder 200 nm were obtained utilizing the parameters of Example 1utilizing 30% ganaxolone, 2% HPMC, 0.1% SLS, 0.1 to 0.2 mm ZrO₂ beads at80% volume with a milling residence time of about 2 hours.

Example 8

In Example 8, ganaxolone particles with an effective particles sizeunder 250 nm were obtained utilizing the parameters of Example 1utilizing 30% ganaxolone, 10% polyvinylpyrrollidinone/vinyl acetate,0.1% SLS, 0.4 to 0.6 mm glass beads at 85% volume with a millingresidence time of about 1 hour.

Example 9

The dispersion from a previous example, before addition offlavoring/sweeteners/preservatives is sprayed in a fluidized bedgranulator (e.g. Wurster column) maintaining a bed temperature of 80° C.onto sucrose spherical beads of about 50 um diameter. The ganaxolonecomposition is sprayed at a level of about 30-40% weight to bead weightand is dried. These ganaxolone microparticulate beads can be filled intogelatin capsules for an immediate release formulation or some of thebeads may be re-introduced into the granulator and an Eudragit L30 D 55dispersion is applied with spray guns facing downward to a 0.5% coatinglevel (weight/weight). These coated beads can now be used with theuncoated beads in a automatic capsule filler at a 40%/60% ratio(uncoated/coated) to provide a 300 mg Ganaxolone dose in a total weightof about 800 mg.

Example 10 Dissolution Testing for Ganaxolone Formulations

Generally, all experiments are conducted at 36° C. to 38° C. Thedissolution medium preferably is SGF or SIF containing 10% of sodiumlauryl sulfate (SLS). The volume of the medium is 900 mL. The operatingspeeds are 75 rpm for Apparatus 1 (basket) and 50 rpm for Apparatus 2(paddle) for solid-oral dosage forms and 25 rpm for suspensions. A40-mesh screen is used in almost all baskets, but other mesh sizes maybe used when the need is documented by supporting data.

Apparatus 2 is generally preferred for tablets. Apparatus 1 is generallypreferred for capsules and for dosage forms that tend to float or thatdisintegrate slowly. A sinker, such as a few turns of platinum wire, maybe used to prevent a capsule from floating.

The test time is generally 30 to 60 minutes, with a single time pointspecification for pharmacopeia purposes. To allow for typicaldisintegration times, test times of less than 30 minutes are to be basedon demonstrated need. Dissolution test times and specifications usuallyare established on the basis of an evaluation of dissolution profiledata. Typical specifications for the amount of active ingredientdissolved, expressed as a percentage of the labeled content (Q), are inthe range of 70% to 80% Q dissolved. A Q value in excess of 80% is notgenerally used, as allowance needs to be made for assay and contentuniformity ranges.

For an oral dispersion, add 20 ml or a volume equivalent to 1000 mgganaxolone to each Type II vessel at 75 RPM paddle speed containing 500mL SGF containing 10% SLS at 36 to 38° C. and at 45 minutes obtain a 5ml sample via syringe. Filter 3 ml from each container through a syringefitted filter disk (0.05 micron) into an eppendorf type centrifuge tubeand centrifuge at 10000 RPM for 30 minutes. Carefully pipette 2 ml ofsupernatant from the tube into a 10 ml volumetric flask. Dilute to 10 mlwith methanol and stopper and invert at least 5 times.

Analyze a sample from each volumetric in duplicate with a validated HPLCassay as follows:

Column: Waters, SunFire, 250×4.6 mm, 5 um

Mobile phase: ACN/MeOH/water=65/5/30 (v/v)

Flow rate: 1.0 ml/min

Detection: RI

Sample conc.: 0.1 to 0.4 mg/ml mg/ml in MeOH

Run time: 45 min

Injection volume: 50 ul

Ganaxolone: RT˜20 min

Make a standard solution of ganaxolone at 1 mg/ml in methanol and diluteto 0.5, 0.25 and 0.125 mg/ml in methanol and inject 50 μl of eachconcentration before and after each duplicate run. Plot the resultsagainst the standard curve to determine the % ganaxolone dissolved. Fora pulsatile or delayed release solid dosage form, the general method issimilar except that 10% SLS in SGF is used initially (first hour) andthen the media is replaced with SIF containing 10% SLS and anotherdissolution period is evaluated (3 hours). Using USP intestinal fluidadjusted to pH 6.8, approximately 70% of the weight of the entericcoated Ganaxolone particles will be released within 3 hours at 75 RPMpaddle speed.For drug release profiles for Ganaxolone formulations, see Example 29.

Example 11

Purpose-bred Beagle dogs are obtained and housed in a USDA-approvedfacility in accordance with AAALAC guidelines. Expected dog weights arefrom 8 to 12.0 kg at the beginning of the evaluation, and are weighedprior to each period of the study. Animals are block randomized intogroups of 3 per treatment. Each study will test ganaxolone formulations(as described in Examples 1-3) along with a reference group which isadministered a conventional ganaxolone-β-cyclodextrin formulation(reference formulation). Fasted animals are fasted overnight withoutwater prior to each study day. Designated fed dogs are fed a can (about400 gm) of Alpo “Chunky with Beef for Dogs,” which has 55% of totalcalories from fat, approximately 45 minutes prior to dosing. Whenadministering aqueous dispersions, test ganaxolone aqueous dispersionformulations and ganaxolone reference formulations are diluted withdeionized water within 2 hours of dosing to deliver about 10 mg/kgganaxolone in a volume of 2.0 ml/kg. If the liquid suspension is to beadministered without dilution, a dose of 5 to 10 mg/kg is given via oralgavage followed by a 7.5 to 10 ml/kg water flush. When administeringganaxolone capsules, both test capsule and reference capsules are givenin a dose of about 10 mg/kg. Capsules are administered orally as istypical. Standard laboratory chow and water are offered ad libitum 4 hafter dosing. To eliminate the variability of drug absorption among thedogs, all studies should be conducted in a randomized crossover design.Approximately 2 milliliters of blood sample are withdrawn with a 21 Gneedle and via direct venipuncture sampling at predose, 15 min, 30 min,1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 24 h and 48 h. Blood is immediatelytransferred to a potassium EDTA blood collection tube (VACUTAINER,Becton Dickinson, Franklin Lakes, N.J., USA) and is stored on ice untilthe samples are centrifuged at 2500-4000 rpm for 15 min. The plasma istransferred to polypropylene tubes, and samples are stored at −70° C.until analyzed by liquid chromatography/tandem weight spectrometry(LC/MS/MS).

A validated method using liquid chromatography/atmospheric pressurechemical ionization tandem weight spectrometry (LC/APCI-MS/MS) for thedetermination of ganaxolone in dog plasma is used for the analysis ofthe all samples. This method is conducted in accordance with thevalidated method previously published (Ramu et al Journal ofChromatography B, 751 (2001) 49-59).

Example 12 PK Data Processing

WinNonlin v. 3.1 (Scientific Consulting, Inc., Apex, N.C.) is used fornon-compartmental analysis of the data. Area under the plasmaconcentration—time curve (AUC_(0-72 h)) is calculated from observedplasma concentrations from 0 to 72 h. Any plasma concentrations belowthe limit of quantitation are set equal to zero. Geometric andarithmetic mean and geometric standard error of the mean (S.E.M.) ofAUC, observed maximum plasma concentration (C_(max)), and time ofC_(max) (T_(max)) can be calculated with Microsoft Excel. Treatment andanimal effects on the AUC values and observed C_(max) are determinedwith the statistical programs of SAS (SAS Institute, Inc., Cary, N.C.,USA). Also, an interaction model with dog, formulation, and fed/fastedstate is examined to confirm the interaction of food with formulation.The AUC and C_(max) values are log-transformed to normalize thedistributions. The Wilcoxon matched-pairs signed ranks test is used toevaluate differences in T_(max) values between groups. Differences areonly considered significant at p≦0.05.

Example 13 Ganaxolone Sub-Micron Particle Suspensions

Ganaxolone submicron particle suspension formulations comprising HPMC,SLS and PVA as stabilizers show useful stability profiles under storageconditions. Submicron particle formulations containing 5 wt % ganaxolonebased on the total weight of the formulation and varying amounts ofHPMC, SLS and PVA were stored at ambient temperature for 7 months.Visual assessments were made with regard to appearance of theseformulations. The results are shown in Table 2.

TABLE 2 Non-preserved ganaxolone particle formulations containing HPMC,SLS and PVA HPMC SLS PVA Entry (wt %) (wt %) (wt %) Visual Assessmentafter 7 Months 1 2 0.2 1 white suspension, trace amount of solid onbottom 2 2 0.2 1.5 white suspension, small amount solid at bottom 3 20.2 2 white suspension, small amount of solid at bottom 4 2 0.2 2.5white suspension, some solid at bottom 5 2 0.2 3 settled, partiallyclear liquid on top 6 2 0.2 3.5 settled, near clear liquid on top 7 20.2 4 settled, clear liquid on top 8 5 0.3 1 white suspension, noapparent settling 9 5 0.3 1.5 white suspension, small amount of solid atbottom 10 5 0.3 2 white suspension, some solid at bottom 11 5 0.3 2.5white suspension, some solid at bottom 12 5 0.3 3 two layers, partiallyclear layer on top 13 5 0.3 3.5 settled, clear liquid on top 14 5 0.3 4settled, clear liquid on top 15 5 0.2 1 white suspension, no apparentsettling 16 2.5 0.2 1.25 white suspension, no apparent settling

Example 14 Physical Stability in Gastric and Intestinal Fluids

Physical stability of ganaxolone particle suspension formulations insimulated gastric and intestinal fluids were tested at 36-38° C.unstirred unless otherwise specified.

Ganaxolone suspension formulations containing HPMC and a surfactant suchas SLS or sodium docusate or DOSS, prepared as described in Example 39underwent flocculation in SGF and SIF. Test results for twoformulations, Ex-39F (15% GNX, 7.5% HPMC and 0.3% SLS) and Ex-39E (15%GNX, 2.5% HPMC and 0.1% DOSS) are shown in Table 3. The particle sizegrowth occurred primarily in the first 1 to 1.5 h after the SGF or SIFtreatment, as the D50 values reached micron levels after 90 min (entries2 and 3, Table 3). It is interesting to note that these formulations arequite stable in deionized water (entries 1 and 5).

TABLE 3 Stability of ganaxolone particle formulations containing onlyHPMC and SLS or DOSS in various fluids (initial D50: 106 nm) at 36° C.to 38° C. Entry Formulation Testing Conditions D50 1 Ex-39F Water, 90min   148 nm 2 Ex-39F SIF, 90 min 1.341 um 3 Ex-39F SGF, 90 min 1.722 um4 Ex-39F Water, 3 h   124 nm 5 Ex-39F SIF, 3 h 2.581 um 6 Ex-39F SGF, 3h 1.787 um 7 Ex-39E SGF, 100 min 1.382 um 8 Ex-39F 0.2N NaCl solution,90 min 1.349 um

Example 15 Ganaxolone Suspension Formulations Containing PolyvinylAlcohol (PVA)

The stabilization effect of PVA is demonstrated by formulation Ex-40A.This formulation was prepared by diluting the final milling slurry asdescribed in Example 40 (Ex-40) with a diluent containing appropriateamounts of HPMC, PVA and SLS (Table 4, entries 1 and 2) in deionizedwater. After 3 h, the D50 values grew only about 19 nm from an initialof 142 nm. As a comparison, the milling slurry Ex-40 which does notcontain PVA underwent flocculation under the same conditions with theD50 value increasing to 360 nm in SIF and 699 nm in SGF from the sameinitial value of 142 nm (entries 4-5). Further, formulation Ex-49A,having nearly identical composition to those of formulation Ex-40Aexcept containing no PVA, showed a D50 value of 300 nm after 3 h insimulated gastric fluid, an increase of 176 nm from the initial D50 of124 nm (entry 4).

TABLE 4¹ Effect of PVA on Ganaxolone Suspension Stability in SGF and SIFGNX HPMC SLS PVA D50 Test Entry Formulation % % % % (nm) Conditions 1Ex-40A 5 5 0.3 1 161 SGF, 3 h 2 Ex-40A 5 5 0.3 1 157 SIF, 3 h 3 Ex-49A 55 0.1 0 300 SGF, 3 h 4 Ex-40 25 2 0.1 0 699 SGF, 3 h 5 EX-40 25 2 0.1 0360 SIF, 3 h ¹Percentages based on w %/total formulation wt andcondition include storage at 36° C. to 38° C. without stirring

Example 16 Effect of Ganaxolone/HPMC Ratio on Ganaxolone SuspensionFormulation Stability In SGF and SIF

Ganaxolone to HPMC ratio is important to ganaxolone suspensionformulation stability in SGF and SIF. Ganaxolone suspension formulationscontaining 15 wt % ganaxolone, 3 wt % HPMC, 1 wt % PVA, 0.1 wt %methylparaben, 0.02 wt % propylparaben, and 0.05-0.2 wt % SLS indeionized water showed increase in D50 value of 155 to 261 nm in SGF(entries 2-3, Table 5) after 2 h. The increase in D50 does not correlatewith the concentrations of SLS. Diluting these formulations withadditional HPMC to 5 wt % ganaxolone and 5 wt % HPMC while keeping othercomponents constant resulted in particle size growth of only <28 nm in70 min (entries 5-11 and 13, Table 5). As shown in Table 2, the particlesize growth primarily occurred during the first 1 to 1.5 h of treatment.Thus these formulations were significantly more stable in SGF than thosehaving larger ganaxolone to HPMC ratios. Increasing HPMC level to 8.5%provided little additional stabilization benefit. The data also showedthat the exact level of SLS in these formulations had little impact ongastrointestinal stability.

Formulations in entries 14-16 of Table 5 had 0.2% methylparaben and hadsimilar stability performance in SGF and SIF.

TABLE 5 Gastric and Intestinal Stabilities of Ganaxolone ParticlesMethyl Propyl GNX HPMC SLS Paraben Paraben PVA D50 Test Entry wt % wt %wt % wt % wt % wt % (nm) Conditions¹ 1 5 3 0.05 0.1 0.02 1 171 Initial 215 3 0.05 0.1 0.02 1 331 SGF, 2 h 3 15 3 0.1 0.1 0.02 1 326 SGF, 2 h 415 3 0.2 0.1 0.02 1 432 SGF, 2 h 5 5 5 0.2 0.1 0.02 1 180 initial 6 5 50.2 0.1 0.02 1 182 SGF, 70 min 7 5 5 0.2 0.1 0.02 1 190 SIF, 70 min 8 55 0.1 0.1 0.02 1 209 SGF, 70 min 9 5 5 0.05 0.1 0.02 1 204 SGF, 70 min10 5 5 0.025 0.1 0.02 1 207 SGF, 70 min 11 5 5 0.017 0.1 0.02 1 203 SGF,70 min 12 5 8.5 0.017 0.1 0.02 1 201 SGF, 70 min 13 5 5 0.025 0.1 0.02 2202 SGF, 70 min 14 5 5 0.017 0.2 0.02 1 185 Initial 15 5 5 0.017 0.20.02 1 209 SGF, 3 h 16 5 5 0.017 0.2 0.02 1 213 SIF, 3 h ¹Testtemperature is the same as that described in Example 14.

Example 17 Formulations Containing Sodium Benzoate as Preservatives

Ganaxolone suspension formulations containing sodium benzoate aspreservatives with citric acid/sodium citrate (pH 4.0) as bufferingagents were also evaluated. With 0.17 wt % sodium benzoate, 0.13 wt %citric acid and 0.01 wt % sodium citrate added, two formulationscontaining of 5 wt % ganaxolone, 5 wt % HPMC, 1 wt % PVA, and 0.1 wt %SLS in deionized water with initial D50 values of 196 and 321 nmrespectively showed good stability against flocculation in both SGF andSIF (Table 6).

TABLE 6 SGF and SIF stabilities of ganaxolone suspension formulationscontaining sodium benzoate as preservatives citric Sodium D50 (nm) noacid, benzoate, Sodium sonication/1 min Testing Entry wt % wt % Citrate,wt % sonication Conditions¹ 1 0.13 0.17 0.01 196/176 Initial 2 0.13 0.170.01 222/191 SGF, 3 h 3 0.13 0.17 0.01 248/201 SIF, 3 h 4 0.13 0.17 0.01321/314 Initial 5 0.13 0.17 0.01 327/320 SGF, 3 h 6 0.13 0.17 0.01328/321 SIF, 3 h ¹Test temperature is the same as that described inExample 14.

Example 18 Effect of PVA on Cmax

The addition of PVA to ganaxolone suspension formulations reduces theC_(max) levels. C_(max) levels were determined for ganaxolone suspensionformulations containing 1:1 GNX/HPMC (wt %), SLS (0.2-0.4% SLS/GNX), andwith and without PVA (20% PVA/GNX). Particles of 110 nm, 140 nm, and 320nm were orally administered into beagle dogs at a dose of 5 mg/kg underfed and fasted conditions. The pharmacokinetics results are shown inTable 7. The formulation with no PVA (Ex-18A) achieved higher exposurethan those with PVA (Ex-18B and Ex-18C). However, addition of PVAreduced variability between the fed and fasted states especially for theAUC values. The ratio of C_(max) to AUC was also lower with PVA added.Formulation Ex-18C is identical to Ex-18B except for added preservatives(0.1 wt % MP, 0.02 wt % PP and 0.09 wt % sodium benzoate at pH 4) andparticle size is larger due to the presence of the preservative. It issurprisingly found that the Ex-18C formulation had higher exposure thanEx-18B formulation despite that the particle size (D50) of Ex-18C ismore than double those of Ex-18B (320 nm vs. 140 nm). The Ex-18Cformulation shows even less variability as well as enhanced totalexposure as compared to the smaller particle size formulation (Ex-18A).The food effect is slightly greater in the optimized suspension due toprolonged drug absorption due to larger particle size.

TABLE 7 Comparative PK results in beagle dogs for ganaxolone suspensionformulations with and without PVA at comparable dose levels (5 mg/kg)Formu- Particle lation Size PVA/ C_(max) AUC_(0-72 hr) Food Reference(D50) Preservative (ng/mL) (ng * h/mL) Intake Ex-18A 110 nm None/None448 ± 96 2422 ± 1059 Fasted Ex-18A 110 nm None/None 1194 ± 104 4637 ±2600 Fed Ex-18B 140 nm Yes/None 268 ± 36 1643 ± 295  Fasted Ex-18B 140nm Yes/None 640 ± 92 3525 ± 1190 Fed Ex-18C 320 nm Yes/Yes 243 ± 40 1855± 321  Fasted Ex-18C 320 nm Yes/Yes 642 ± 40 5512 ± 681  Fed

Data provided in Table 8 further demonstrates the reduced variabilitybetween fed and fasted state for ganaxolone formulations containing PVA.The Ex-18D formulation has a particle size of 120 nm, which is verysimilar to that of Ex-18A above. This formulation was identical toEx-18A except PVA was added. In this study, a fed/fasted effect of1.6-1.7×AUC₀₋₇₂(fed): AUC₀₋₇₂(fasted) was obtained.

TABLE 8 AUC(₀₋₇₂₎ AUC_(inf) C_(max) Group (ng * h/mL) (ng * h/mL)(ng/mL) # MEAN SD MEAN SD MEAN SD Formulation 1 1440 460 1616 474 273 45Ex-18D in Fasted Males Formulation 2 2403 422 2624 430 563 92 Ex-18D inFed Males

Data provided in Table 8 further demonstrates the reduced variabilitybetween fed and fasted state for ganaxolone formulations containing PVA.The Ex-18D formulation has a particle size of 120 nm, which is verysimilar to that of Ex-18A above. This formulation was identical toEX-18A except PVA was added. In this study, a fed/fasted effect of1.6-1.7×AUC₀₋₇₂(fed): AUC₀₋₇₂(fasted) was obtained.

TABLE 8 AUC₀₋₇₂ hr AUC_(inf) C_(max) Group (ng * h/mL) (ng * h/mL)(ng/mL) # MEAN SD MEAN SD MEAN SD Formulation 1 1440 460 1616 474 273 45Ex-18D in Fasted Males Formulation 2 2403 422 2624 430 563 192 Ex-18D inFed Males

Example 19 Use of Simethicone in the Milling Process

Presence of simethicone (e.g., at 0.1 wt % level) during the millingprocess results in more stable ganaxolone suspensions (i.e. theparticles experienced less post-milling particle size growth compared tothose produced without simethicone during the milling). The experimentalresults for two nearly identical milling runs except simethicone levelsare shown in Table 9.

TABLE 9 Ingredients Simethicone Residence D50 Milling Size(Concentrations) during Time (end of D50 Run (g) During Milling, wt %milling, wt % (min) milling) (fullycured) Ex-42 1200 ganaxolone(25%),0.1% 27.5 180 327 HPMC(5%), SLS (0.1%), PVA (1%), methylparaben (0.1%),propylparaben (0.02%) Ex-44 1200 ganaxolone (25%), 0 25.4 162 380HPMC(3%), SLS (0.1%), PVA (1%), methylparaben (0.1%), propylparaben(0.02%)

Example 20 Control of Particle Size by Adjusting the Residence Time ofMilling

Milling runs in deionized water are conducted with 1 wt % PVA andappropriate amounts of preservatives in addition to HPMC (3 to 5 wt %)and SLS (0.05 to 0.1 wt %) utilizing 0.1-0.2 mm zirconium oxide beads(entries 1-4, Table 3). Each wt % is based on the total weight of themilling mixture (without zirconium oxide beads). For entries 1, 3, and4, the preservatives were 0.1 wt % methylparaben and 0.02 wt %propylparaben and for entry 5, the preservative was 0.1 wt % sodiumbenzoate buffered with 0.12 wt % citric acid and 0.0093 wt % sodiumcitrate. After the effective particle size (D50 reached between 150-170nm, runs 2 and 3 were stopped, while run 1 was allowed to continue. Datasuggests that continued milling did not reduce the particle size anyfurther. However, it did produce more stable particles compared to theruns with shorter residence time. Further, after run 3 was re-milled twodays later (D50 303 nm) under the same conditions for additional 69 minof residence time (entry 5), the particles became even more stable.

Milling runs were also conducted with only HPMC and SLS. PVA andpreservatives were added post-milling (entries 5-9, Table 10). As in thecase of run 1, longer residence time resulted in more stable particles.

TABLE 10 Post-Milling Particle Size Growth vs. Residence Time Increasein D50 4 Milling D50 at end of Residence weeks after Run milling(nm)^(e) Time (min) milling (nm) 1^(a) 153 75 39 2^(b) 160 25 201 3^(c)162 25.4 209 4^(d) 167 69 23 5^(f) 143 33 177 6^(f) 139 35 156 7^(f) 15534 160 8^(f) 163 24 217 9^(f) 142 68 52 ^(a)Ganaxolone concentration(15%), PVA (1%), methylparaben (0.1%) and propylparaben (0.02%) werepresent during milling; ^(b)Ganaxolone concentration (25%), PVA (1%),sodium benzoate (0.1%), citric acid (0.12%), sodium citrate (0.0093%)and simethicone (0.025%) were present during milling; ^(c)Ganaxoloneconcentration (25%), PVA (1%), methylparaben (0.1%), propylparaben(0.02%) were present during milling; ^(d)Milling slurry of entry 3 (2xdiluted) was re-milled after 2 days; ^(e)Particle size was measured on aHoriba LA-910 particle size analyzer; ^(f)PVA (1%), methylparaben(0.1%), propylparaben (0.02%) were added post-milling.

Example 21 Preparation of Pharmaceutically Useful Ganaxolone SuspensionFormulations (50 mg/mL) from the Milling Slurry

Method A (One-Step Dilution):

A milling slurry of known ganaxolone concentration prepared as describedin Examples 37-52 is diluted with appropriate amount of diluentcontaining appropriate levels of excipients and other necessarycomponents such as preservatives, flavoring, sweetener and antifoamingagent to achieve 50 mg/mL drug concentration.

Method B (Two-Step Dilution):

A milling slurry prepared as described in Examples 37-52 is firstdiluted to an intermediate drug concentration (ca. 80 mg/mL) withappropriate amount of diluent containing appropriate levels ofexcipients and all necessary components such as preservatives, flavoringand sweetener, antifoaming agent. For example, for a milling slurry withan initial ganaxolone concentration of 25 wt % is diluted by mixing onepart of the milling slurry with two parts of the diluent will give theintermediate concentration of 8 wt % which is roughly equivalent to 80mg/mL (assuming the density of the slurry is about 1 g/mL). Theappropriate concentrations of excipients and other components are chosenfor the diluent so that all components are present at the desired levelsafter the intermediate dilution. The precise ganaxolone concentration isthen determined by appropriate assay (e.g. HPLC). The final dilution isperformed with appropriate amount of diluent containing the correctlevels of all excipients and other components.

Example 22 Effect of HPMC, SLS, and PVA Levels on Paraben-ContainingGanaxalone Suspension Formulations

The effect HPMC, SLS, and PVA levels on the stability ofparaben-containing ganaxolone particle formulations was studied. Each ofthe aqueous suspension formulations contains 5 wt % ganaxolone, 0.1 wt %methylparaben, 0.02 wt % propylparaben, each based on the total weightof the formulation, and varying amounts of HPMC, SLS and PVA indeionized water. Visual Assessments were conducted after 7 months ofstorage at ambient temperature to assess the formulation stability. Thecompositions and the stability results are shown in Table 11.

TABLE 11 Paraben-containing ganaxolone suspension formulationscontaining HPMC, SLS and PVA HPMC SLS Visual Assessment after 7 Entry(wt %) (wt %) PVA (wt %) Months 1 2 0.1 3.5 settled, partially clearliquid on top 2 5 0.3 1 white suspension, small amount of solid atbottom 3 5 0.3 1.5 white suspension, some solid at bottom 4 5 0.3 2white suspension, some solid at bottom 5 5 0.3 2.5 white suspension,some solid at bottom 6 5 0.3 3 white suspension, small partially clearlayer on top 7 5 0.3 3.5 settled, clear liquid on top 8 5 0.3 4 settled,clear liquid on top 9 3 0.2 1 white suspension, some solid on bottom 103 0.2 1.5 white suspension, substantial solid on bottom 11 3 0.2 2 whitesuspension, substantial solid on bottom 12 3 0.2 2.5 settled, partiallyclear liquid on top 13 3 0.2 3 settled, partially clear liquid on top 143 0.2 3.5 settled, near clear liquid on top 15 3 0.2 4 settled, clearliquid on top

The data of Table 11 shows that 5 wt % HPMC 0.3 wt % SLS at 0.3 wt %ganaxolone formulations showed good stability with the amount 1 wt % to3 wt % PVA range (entries 2-6). When PVA levels are further increased to3.5 to 4 wt % while the other components are held constant, somesettlement of particles at the bottom and clear liquid on the top of theformulations was observed (entries 7 & 8).

Formulations listed in entries 9-11 showed good stability with theamount of PVA ranging from 1 wt % to 2 wt % while the amounts of HPMC (3wt %) and SLS (0.2 wt %) were held constant. When the PVA levelincreased to 2.5 to 4 wt % while the other components were held constantsome settlement of particles at the bottom and clear liquid on the topof the formulations (entries 12-15) was observed.

There appears to be an optimal compositional range for obtaining goodformulation stability. Less than or equal to 3.5 wt % of PVA (or 0.5 to2.5 wt %) is desirable in obtaining good stability of paraben containingganaxolone formulations, especially at 5 wt % (or 3 wt %) or lower HPMCconcentrations.

Example 23 Effect of Preservative on Ganaxolone Suspension FormulationStability in SGF and SIF

The effect of a preservative on ganaxolone suspension formulationstability in SGF and SIF were studied. Formulations listed in entries1-6, Table 12A contained 8-9.5 wt % of GNX, 4-4.8 wt % of HPMC,0.24-0.29 wt % SLS, 6-7 wt % of sucrose, based on the total weight ofthe formulation. Various amounts of parabens as shown in Table 12A wereadded immediately prior to dispersion and storage in SGF and SIF at36-38° C.

It can be seen from Table 12A that parabens have a stabilizing effect onthe ganaxolone particle formulations in SGF and SIF when addedimmediately prior to dispersion into these media. The median particlesize (D50) grew to around 200-270 nm from the initial value of 106 nm.These results compared favorably to those of the base formulations(without paraben) whose D50 exceeded 1 micron after 90 minutes in SGF orSIF as shown in Table 2. Furthermore, one minute of sonication of theformulations after one-hour of storage reduces the particle sizes toaround 141 to 147 nm.

Significantly, when parabens or sodium benzoate were added as complexingagents after milling and the ganaxolone particles were allowed to cureto reach the end pint where the particles become stable, dispersion andstorage in SGF and SIF at 36-38° C. for 3 h caused virtually no increasein particle size (D50). The results are shown in Table 12B.

TABLE 12A Effect of methylparaben and propylparaben on physicalstability of ganaxolone suspension formulations (Initial D50 106 nm) D50no Test Methylparaben Propylparaben sonication, nm Conditions Entry wt %wt % (1 min sonication) 36 to 38° C. 1 0.07 0 251 (144) SGF, 1 h 2 0.070 187 (141) SIF, 1 h 3 0 0.014 269 (144) SGF, 1 h 4 0 0.014 191 (141)SIF, 1 h 5 0.1 0.02 218 (147) SGF, 1 h 6 0.1 0.02 208 (142) SIF, 1 h

TABLE 12B Test results in SGF and SIF for cured ganaxolone particlescomplexed with a complexing agent^(a) D50 no D50 no sonication,sonication, nm, nm, Initial D50 after storage after storage Complexingunsonicated in SGF, 3 h in SIF, 3 h agent/amount (% (1 min (1 min (1 minEntry w/w) sonication) sonication) sonication) 1 Methylparaben/0.1% 314nm 326 nm 344 nm Propylparaben/0.02% (311 nm) (313 nm) (330 nm) 2 Sodium321 nm 322 nm 329 nm benzoate/0.09% (314 nm) (312 nm) (313 nm) Citricacid/0.12% Sodium citrate/0.093% ^(a)The composition of the testformulation are: 5% ganaxolone, 5% HPMC, 0.1% SLS (all based on totalweight of the formulation).

Example 24 The Synergistic Effect of Preservative and PVA in Combinationon Physical Stability of Ganaxolone Suspension Formulations

The synergistic effect of a preservative and PVA combination onganaxolone suspension formulation physical stability was studied. Allformulations contained 4.5-8 wt % GNX, 2.2-4 wt % HPMC, 0.09-0.24 wt %SLS, 4.5-9 wt % sucrose, based on the total weight of the formulation,and varying amounts of paraben and PVA as shown in Table 13.

TABLE 13 Synergistic effects of parabens and PVA on stabilizingganaxolone suspension formulation in SGF and SIF (initial D50 120 nm)Methyl- D50, nm paraben, Propylparaben PVA, (1 min Test Entry wt % wt %wt % sonication) Conditions¹ 1 0.1 0.02 0 218 (147) SGF, 1 h 2 0.1 0.020 208 (142) SIF, 1 h 3 0.07 0.015 1.3 149 (139) SGF, 1 h 4 0.08 0.0161.1 150 (138) SIF, 1 h ¹Test temperature is the same as that describedin Example 14.

Results in Table 13 indicate that ganaxolone suspension formulationscontaining both parabens and PVA showed additional physical stability inboth simulated gastric (SGF) and intestinal (SIF) fluids. While theganaxolone particle size in formulations containing only parabens grewmore than 80 nm in 1 h in both gastric and intestinal fluid (Table 13,entries 1-2), those in formulations containing ca. 1% PVA in addition tothe parabens grew only slightly (less than 30 nm) (entries 3-4). Theseresults suggest synergies between parabens and PVA in stabilizing theganaxolone particles in gastric and intestinal fluids. Furthermore, oneminute of sonication of the formulations containing both parabens andPVA after one-hour of storage reduces the particle sizes to around 138to 139 nm.

Example 25 Effects of Multiple Preservatives on Pharmacokinetics (PK)

In the following examples, the effect of the combination of parabens andsodium benzoate and/or benzoic acid on pharmacokinetics was studied,versus the effect of sodium benzoate and/or benzoic acid withoutparabens. The particle sizes for both formulations were similar (320 nmfor Ex-18C and 360 nm for Ex-25A). Studies were conducted using bothfasted and fed beagle dogs and the PK results are summarized in Table14.

Results in Table 14 indicate that paraben/sodium benzoate/benzoic acidcombined preserved ganaxolone suspension formulations provide a lowerfood effect (about 3 times) than sodium benzoate alone formulations(about 4 times) at 5 mg/kg. Moreover, the paraben/sodiumbenzoate/benzoic acid combined preserved formulation showed significantimprovement in exposure variability as compared to the sodium benzoateonly formulation.

TABLE 14 Comparative PK results in beagle dogs (5 mg/kg, fed/fasted) forganaxolone particle formulations preserved with sodium benzoate only andsodium benzoate/parabens combination. C_(max) AUC0-72 hours FoodFormulation Preservatives (ng/mL) (ng * h/mL) Intake Ex-25A Sodium 267 ±93 1551 ± 264 Fasted benzoate/ benzoic acid Ex-25A Sodium  802 ± 157 6352 ± 2469 Fed benzoate/ benzoic acid Ex-18C Parabens + 243 ± 40 1855± 321 Fasted sodium benzoate/ benzoic acid Ex-18C Parabens + 642 ± 405512 ± 681 Fed sodium benzoate/ benzoic acid

For liquid formulations amounts of formulation components are given asweight percent of the total formulation weight (w %/w) unless otherwiseindicated. For solid dosage forms formulation components are given as apercent of ganaxolone (w %/GNX). For example, in a solid dosage form,100% HPMC indicates that the weight of HPMC in the formulation is equalto the weight of ganaxolone in the formulation.

Particle size measurements for liquid ganaxolone suspensions are madeusing a Horiba LA 910 Particle Size Analyzer adding liquid ganaxolonesuspension via a 5 ml pipette into the Horiba chamber (containingapprox. 125 ml distilled water that has been blanked) to achieve atungsten light transmittance of 75 to 80%. Other settings are arecirculation setting of 4, stirring setting of 1, and relativerefractive index of 115-010.

Example 26 Spray Layered Ganaxolone Formulation

100 g of a sphere (20-35 mesh) are added to a Glatt GPCG-3 fluidized bedwith Wurster column insert (4 inch), inlet temperature of 50 to 60° C.and air temp of 30 to 50° C. (total air volume approx. 150-200 cubiccm/hr). A 17.6% total solids content slurry containing ganaxolone (197nm, 71% of solids content), hydroxymethylpropylcellulose (Pharmacoat603, 14.9% of solids), SLS (0.1% of solids), sucrose (13.4% of solids),and 30% simethicone emulsion (DC7-9245, 0.1% of solids) with totalweight of sprayed suspension being 697 g (574 ml water), is sprayed(bottom spray) through 1.2 mm nozzles at 10 ml/min and 1.5 bar ofpressure until a layering of 123% % is achieved as compared to initialbead weight.

Dispersion in water (1 g in 300 ml) at 36-38° C. spinning at 75 RPMdemonstrated complete disintegration within 10 minutes. Dissolution ofganaxolone coated sugar beads into SGF or SIF at 0.5 mg/ml at 36-38° C.for 1 hour showed agglomeration (settling in container) and effectiveparticle size of >5 um.

Example 27 Preparation of Dried Solid Ganaxolone Particle Formulations

Ganaxolone particle suspension (1.0 g), prepared as described above inExamples 37-52 is placed in a 25 ml glass scintillation vial fitted ontoa Buchi rotary evaporator. The vial is spun at approx. 150 rpm and thewater bath temperature is set between 70-90° C. Vacuum is graduallyapplied for the initial 2 minutes to minimize bumping. After bumping isno longer a problem, full vacuum is applied (approx. 2-4 mbar) until apowder free of any water or visible condensation is observed (approx. 10min). The vial is then dried on the evaporator for an additional 10-15minutes.

In cases where additional components are required to be added to theganaxolone particle suspension prior to drying, these components areweighed into the vial first and approx. 0.5 g of deionized water isadded to obtain a complete solution. To this solution is then added 1.0g of the ganaxolone particle suspension. The content in the vial isswirled manually. After the content is thoroughly mixed, the vial isfitted onto a Buchi rotary evaporator to dry the content as describedabove.

Example 28 Preparation of Simulated Gastric and Intestinal FluidSimulated Intestinal Fluid (SIF)

Monobasic potassium phosphate (6.8 gm) and sodium hydroxide (0.616 gm)are added into 250 ml of distilled water in a 1000 ml volumetric flaskand swirled until dissolved. 700 ml distilled water is added and the pHchecked. The pH is adjusted to pH 6.8+/−0.1 by adding either 0.2N sodiumhydroxide or 0.2N hydrochloric acid and the volume is brought to 1000ml.

Simulated Gastric Fluid (SGF)

Sodium chloride (2 gm), 750 ml distilled water, and 7.0 ml ofconcentrated hydrochloric acid are added into a 1000 ml volumetricflask. The flask is swirled to mix and the volume brought to 1000 mlwith distilled water. The pH should be approx. 1.2.

Example 29 Dispersion Tests of Solid Ganaxolone Particle Formulations inSimulated Gastric and Intestinal Fluid

The solid ganaxolone particle formulation is dispersed in simulatedgastric and intestinal fluid and their dispersibility is monitored byvisual assessment for flocculation and particle size measurement using aHoriba-LA-910 particle analyzer. The detailed procedure is describedbelow.

In-Process Immediate Release Blend or Liquid Dispersion

In a 25 ml translucent HDPE vial (total fill volume) with HDPE cap isplaced appropriate amount of ganaxolone formulation (e.g. 9.8 mg driedganaxolone powder containing 76% ganaxolone and appropriate levels ofexcipients) to achieve a final ganaxolone concentration of approx 0.5mg/ml when diluted with 15 ml of simulated gastric or intestinal fluid.After adding the dispersant, the vial is shaken manually untilformulation is completely dispersed. The vial is then placed in a heatedoil bath at 37° C. unstirred unless specified otherwise until thedesired test time. The vial is removed from the bath and inspectedvisually for signs of flocculation. It is then shaken before particlesize measurement using a Horiba-LA-910 particle analyzer. Typically thematerials are incubated for 3 hours to approximate the human gastricemptying period.

Particle Size Measurement

If measuring coated beads where the bead core contains insolublematerials, calculate the weight of bead core in the SIF or SGFexperiment, disperse an equal weight of core beads into the same volumeof SIF or SGF and pour the entire amount into 120 gm of distilled waterin the Horiba LA-910 chamber. Blank the instrument and drain. Add 120 gmdistilled water and pour the entire quantity of incubated formulation(in 15 ml SGF or SIF) into the Horiba chamber. Measure the particlesize. This process subtracts any particle size interference from thecore beads. In the case of MCC cores, which are insoluble, measure theparticle size by the method used for liquid suspension. After theinitial particle size measurement of the re-dispersed ganaxoloneformulation, sonicate at the low power setting on the Horiba LA-910 for1 minute, unless specified otherwise, and re-measure the particle size.As for any suspension or dispersion study the D50 difference as well asoverlapping the 2 traces can give a qualitative indication of how muchof the formulation forms a loose agglomerate.

Dispersion of Ganaxolone Suspensions, Tablets and Capsules (Immediateand Delayed Release)

Place the ganaxolone solid dosage form in a type II dissolutionapparatus with basket at 37° C. containing SGF at a 0.5 to 1.0 mg/mlganaxolone concentration for the immediate release component. Stir at 75RPM and sample at 1 hour for the particle size. Measure the particlesize as described above (15 mL aliquot) using a direct measurementmethod if all excipients are water soluble or by filtering through a 5micron filter or by blanking using the same blend quantity minusganaxolone dispersed under the same conditions as the immediate releaseganaxolone coated beads above. If a delayed release or pulsatile releasedosage, after the SGF incubation, replace the SGF with SIF (to make 0.5to 1 mg/ml of ganaxolone in the delayed release component. Utilize thesame conditions as for SGF but let stir for 3 hours. Sample and measurethe particle size as described above for the SGF portion of the study.

Example 30 Ganaxolone Dispersion Test Results

Table 15 shows test results for a ganaxolone particle suspensionformulation (12.6% ganaxolone, 2.6% HPMC, 0.026% SLS, 0.018% simethiconeemulsion (30% simethicone in water) and 2.4% sucrose) and two otherdried forms (rotary evaporation dried and spray layered onto sucrose ormicrocrystalline cellulose beads). The spray layered form was preparedby evaporating the layering slurry onto sugar beads (Paulaur 30/35 mesh)through a fluidized bed coating process yielding approximately 35%ganaxolone loading (% wt GNX/% total bead wt), as assayed byHPLC—refractive index. Although the initial liquid formulation had D50values of 343 and 361 nm after 3 h in both gastric and intestinal fluidsat 36-38° C., the two dried forms had D50 values in the range of 11-25micrometers in the same test. Further, the action of 1 minute sonicationdid not return D50 to its original value.

TABLE 15 Dispersion Results of Ganaxolone suspension containing HPMC,SLS, Sucrose and Simethicone (no complexing agent added) or after theremoval of water via Rotary Vacuum Evaporation (Rotovap) or SprayLayered onto Sugar Beads D50 (μm)/ D50 after1 min Visual DispersionEntry Dosage Form sonication Observation conditions¹ 1 layering slurry0.211/0.202 Uniform Initial suspension 2 layering slurry 0.343/0.291Flocculated SGF, 3 h 3 layering slurry 0.361/0.247 Flocculated SIF, 3 h4 Rotvap Dried 0.325/0.305 Uniform Distilled water, suspension ambient,5 min 5 Rotvap Dried 11.1/2.2  flocculation SGF, 100 min 6 Rotvap Dried11.3/3.1  flocculation SIF, 100 min 7 Layered on sugar 19.5/8.8 flocculation SGF, 3 h beads 8 Layered on sugar 25.5/7.6  flocculationSIF, 3 h beads ¹Temperature for SGF and SIF tests is the same as thatdescribed in Example 14.

Example 31 Effects of Sucrose, HPMC, SLS and PVA on Ganaxolone ParticleFormulations without a Complexing Agent (Table 16)

As the data in Table 16 shows, higher level of SLS resulted in lessparticle growth upon dispersion in simulated gastric and intestinalfluids (entries 1-2) for non-Complexed ganaxolone particle formulations.Doubling the sucrose level from 46.6 to 98.3%, while keeping the SLSlevel constant showed positive, but smaller effects on dispersion (entry3). Addition of ca. 10% PVA showed similar effect to that of doublingsucrose level at the same SLS level (entry 4).

TABLE 16 Dispersion Test Results of Dried Non-Complexed GanaxoloneParticle Formulations ((initial D50: 147 nm, from Milling run Ex-21) inBoth Simulated Gastric and Intestinal Fluids Sucrose HPMC SLS PVA D50(μm)/ % % % % 1 min Dispersion Entry (w/GNX) (w/GNX) (w/GNX) (w/GNX)sonication Conditions ¹ 1 46.6 22.1 0.93 0 24.7/1.2  SGF 14.9/1.6  SIF 246.6 22.1 2.79 0 0.984/0.26  SGF 1.21/0.28 SIF 3 98.3 22.1 0.98 013.9/0.30 SGF 12.2/0.28 SIF 4 48.8 22.1 0.98 9.75 12.3/3.19 SGF11.2/4.22 SIF ¹ Conditions are the same as Example 14

Example 32 Dispersion of Solid Ganaxolone Particle Formulations with aParaben Complexing Agent Example 32a Solid Particles Prepared from6-Month Old Suspension Formulation Containing a Complexing Agent

Solid ganaxolone particles prepared from a 6-month old stable suspensionformulation as described in Example 45 (Ex-45) containing 52% HPMC,10.4% PVA, 1.25% parabens, and 1.0% SLS re-dispersed well in bothsimulated gastric and intestinal fluids at 36-38° C. (entry 5, Table17). Addition of 54.8% of sucrose further improved the re-dispersibilityespecially in simulated gastric fluid (entry 3). Adding additional 2.3%SLS to this formulation further reduced particle growth upon dispersion,particularly in simulated gastric fluid (entry 4). Doubling the sucroselevel also provided positive stabilization effect (entry 2).

TABLE 17 Dispersion Test Results of Dried Stable Ganaxolone Formulationscontaining a complexing agent ((Ex-45) in Simulated Gastric andIntestinal Fluids (D50: 205 nm) Sucrose HPMC SLS Parabens^(a) D50 (μm)/% % % % 1 min disperse Entry (w/GNX) (w/GNX) (w/GNX) (w/GNX) sonicationconditions^(b) 1 104.2 52.1 1.0 1.25 0.203 DI water, ambient 2 104.252.1 1.0 1.25 0.329/0.215 SGF, 2 h 0.333/0.217 SIF, 2 h 3 54.8 52.1 1.01.25 0.363/0.213 SGF, 3 h 0.333/0.216 SIF, 3 h 4 54.8 52.1 3.3 1.250.314/0.211 SGF, 3 h 0.328/0.219 SIF, 3 h 5 0 52.1 1.0 1.25 0.408/0.285SGF, 3 h 0.367/0.283 SIF, 3 h ^(a)1.04% methylparaben and 0.21%propylparaben; ^(b)Temperature for SGF and SIF tests is the same as thatdescribed in Example 14.

Example 32b Solid Particles Prepared from a 1 Week Old GanaxoloneSuspension Formulation Containing Methylparaben as the Complexing Agent

Solid ganaxolone particles prepared from a 1-week old methylparabensuspension formulation containing 0.98% methylparaben in addition to24.4% HPMC, 0.15% simethicone (30% emulsion in water), 1.46% SLS weretested for dispersion in both simulated gastric and intestinal fluids at36-38° C. (Table 18). Consistent with previous observations, higherlevel of SLS resulted in less particle size growth upon dispersion(entry 2) in both gastric and intestinal fluid. Addition of 25% sucroseto the above formulation further reduced particle size growth upondispersion (entry 3). Addition of 9.76% PVA provided less obviousbenefit.

TABLE 18 Dispersion Test Results of Dried Ganaxolone (GNX) ParticleFormulations Prepared from Milling Slurry Containing Methylparaben inGastric and Intestinal Fluids (initial: 310 nm nm): Effects of Sucrose,SLS, PVA and Simethicone (all % expressed as wt %/GNXwt) D50 (μm)/Methyl- D50 (μm) Sucrose HPMC 30% SLS paraben PVA after 1 min DispersionEntry % % SE % % % sonication Conditions¹ 1 0 24.4 0.15 1.46 0.98 030.0/0.333 A 19.5/0.312 B 2 0 24.4 0.15 2.93 0.98 0  5.6/0.303 A 8.2/0.302 B 3 25 24.4 0.15 2.93 0.98 0 0.517/0.291  A 0.807/0.288  B 424.4 24.4 0.15 2.93 0.98 9.76 2.29/0.309 A 2.13/0.328 B 5 0 24.4 0.492.93 0.98 0 9.02/0.304 A 11.23/0.314  B 6 0 24.4 0.98 2.93 0.98 07.66/0.315 A 9.44/0.311 B ¹Re-disperse conditions: A, simulated gastricfluid, 36-38° C., 3 h; B. Simulated intestinal fluid, 36-38° C., 3 h. SE= Simethicone

Example 33 Head to Head Comparison of Re-Dispersibility in SimulatedGastric and Intestinal Fluids of Solid Ganaxolone Particles: With andwithout a Complexing Agent (Methylparaben) Added

Two liquid ganaxolone particles formulations were prepared as describedin Examples 51 and 52 respectively: one contained 0.98% methylparaben inaddition to 24.3% HPMC and 1.46% SLS (Ex-51) and the other one containedonly comparable levels of HPMC and SLS (Ex-52). When these two liquidformulations tested side by side in simulated gastric and intestinalfluid at 37° C., the complexing agent containing formulation Ex-51(entry 1, Table 19) showed significantly less particle size growthcompared to the formulation Ex-52 without the complexing agent (entry 2,Table 19). With additional amounts of HPMC and SLS added (entries 3-4,table 19), similar results were obtained. These results are consistentwith those discussed earlier. Solid ganaxolone particles prepared fromthe suspensions listed in entries 3-4, Table 19 were re-dispersed insimulated gastric and intestinal fluid, the paraben-containingformulation showed less particle size growth than its no-parabencounterpart (entries 3-4, Table 20).

TABLE 19 Gastric and intestinal stability study of formulations preparedfrom Ex-51 and Ex-52: Effect of Methyl paraben as the complexing agent(formulations tested as suspension) D50 (μm) No Methyl- Sonication/ HPMCSLS % paraben 1 min Test Entry (w/GNX) (w/GNX) % (w/GNX) sonicationconditions¹ 1 24.4 1.46 0.98 0.382/0.324 A 0.394/0.326 B 2 23.5 1.41 00.897/0.290 A  7.36/0.283 B 3 47.1 2.82 0 0.828/0.258 A 0.933/0.267 B 448.8 2.93 0.98 0.350/0.314 A 0.353/0.313 B ¹dispersion conditions: A,simulated gastric fluid, 36-38° C., 3 h; B. Simulated intestinal fluid,36-38° C., 3 h.

Additional comparative dispersion studies of solid ganaxolone particleswith and without parabens were carried out in simulated gastric andintestinal fluids. Ganaxolone particles with 0.98% methylparaben as thecomplexing agent (allowed to cure for 1 week) showed significant lessparticle growth upon dispersion at 37° C. than that containing nocomplexing agent (entries 2-3, Table 20). Presence of 9.4-9.8% PVA didnot significantly alter the dispersion behaviors of solid ganaxoloneparticles with and without the complexing agent (entries 1&4, 2&3, table20). For formulation listed in entry 4, Table 19, addition of ca 52% ofsucrose significantly reduced particle size growth upon dispersion(entry 8, table 6.6). However, doubling the sucrose level did not showany significant additional benefit (entry 9, Table 20). Similar trendswere observed for solid ganaxolone formulations containing no complexingagent (entries 6&7, 10&11, Table 20). Compared with formulation listedin entry 8, Table 20, lowering the levels of sucrose, HPMC and SLSresulted in larger particle size upon dispersion, especially insimulated intestinal fluid (entry 5, Table 20).

TABLE 20 Comparative Dispersion Results of Dried Ganaxolone ParticleFormulations Prepared from a ganaxolone suspension with Methylparaben(Ex-51, 24.4% HPMC, 0.98% methylparaben, initial D50: 148 nm, complexedD50: 310 nm cured for 7 days at 20° C.) and without Methylparaben(Ex-52, D50: 147 nm) in Gastric and Intestinal Fluids: Effects ofSucrose, SLS, PVA Sucrose SLS PVA Methyl- D50 (μm) % HPMC % % paraben %No sonication/1 disperse Entry (w/GNX) (w/GNX) (w/GNX) (w/GNX) (w/GNX)min sonication conditions¹ 1 0 48.3 2.90 9.8 0.98 0.69/0.332 SGF, 3 h1.14/0.336 SIF, 3 h 2 0 46.6 2.80 9.4 0 4.04/0.768 SGF, 3 h 3.57/0.677SIF, 3 h 3 0 47.1 2.82 0 0 4.02/1.12  SGF, 3 h 4.13/1.24  SIF, 3 h 4 048.8 2.93 0 0.98 0.636/0.314  SGF, 3 h 1.28/0.322 SIF, 3 h 5 15.4 32.91.9 0 1.3 0.754/0.317  SGF, 3 h 2.64/0.322 SIF, 3 h 6 47.0 23.5 2.8 0 02.89/0.303 SGF, 3 h 15.87/0.296  SIF, 3 h 7 94.1 23.5 2.8 0 0 6.89/0.280SGF, 3 h 13.98/0.288  SIF, 3 h 8 51.8 49.3 3.0 0 0.98 0.366/0.283  SGF,3 h 0.413/0.304  SIF, 3 h 9 103.8 46.7 2.8 0 0.98 0.383/0.292  SGF, 3 h0.588/0.304  SIF, 3 h 10 52.1 52.1 3.1 0 0 2.09/0.301 SGF, 3 h3.94/0.316 SIF, 3 h 11 104.4 47.1 3.1 0 0 2.72/0.293 SGF, 3 h 5.46/0.301SIF, 3 h ¹Temperature for SGF and SIF tests is the same as thatdescribed in Example 14.

Example 34 Effect of Salts on Dispersion of Dried Ganaxolone ParticleFormulations with and without a Complexing Agent Added

Sodium chloride is very effective in improving dispersion of a driedganaxolone particle formulation (described in Example 51) cured with acomplexing agent in both simulated gastric and intestinal fluid. Theresults are shown in Table 21. At 1.5 w %/GNX level, sodium chloridereduced D50 from 13.2 μm to 3.17 μm upon dispersion in simulated gastricfluid at room temperature (entries 1-2). Raising the sodium chloridelevel to 2.0% relative to ganaxolone, under the same conditions,decreased D50 to 0.548 μm in gastric fluid. Above 3.0%, sodium chlorideessentially prevented particle size growth upon dispersion in gastricand intestinal fluid (entries 6-9, 11, Table 21). At low sodium chloridelevel, additional stabilization effect can be obtained by adding a watersoluble spacer which has more plasticity than salts. The water solublespacer used to illustrate this point is sucrose. As shown in entry 4, at1.5% sodium chloride level, addition of 2.5% of sucrose (relative toganaxolone) reduced D50 to the same level as 3.0% sodium chloride.Increasing the sucrose level to 5% provided little additional benefit(entry 3). For the stabilized solid ganaxolone particle formulationcontaining methylparaben as a complexing agent and cured for >7 days,the increase in D50 values is primarily caused by loose aggregation upondispersion. A 1 min sonication at the low power setting readily reversesthese loose aggregates back to individual smaller particles, as shown inTable 21.

For the regular ganaxolone particle formulation that has not beenstabilized by a complexing agent, addition of sodium chloride at a levelas high as 23.5% relative to ganaxolone resulted in D50 of 22.7 μm upondispersion in simulated gastric fluid at room temperature. Thissignificant increase in D50 upon dispersion can only be partiallyreversed after 1 min low power sonication (entry 12, table 21). Theactual particle distribution traces (after 1 min low power sonication)for entries 9 (with methylparaben) and 12 (without methylparaben) areshown in FIG. 5.

TABLE 21 Effect of sodium chloride on dispersion of dried ganaxoloneparticles (with and without complexing agent) and in simulated gastricand intestinal fluid (SGF and SIF) Simethicone Methyl- D50(μm) HPMC SLS30% emulsion paraben NaCl Sucrose no sonication/ % % % % % % D50(μm)after 1 Dispersion Entry w/GNX w/GNX w/GNX w/GNX w/GNX w/GNX minsonication conditions 1 24.4 1.46 0.15 0.98 0 0  13.2/0.332 SGF, 5 min,rt 2 24.4 1.46 0.15 0.98 1.5 0  3.17/0.337 SGF, 5 min, rt  4.45/0.353SIF, 5 min, rt 3 24.4 1.46 0.15 0.98 1.5 5 0.364/0.316 SGF, 5 min, rt0.396/0.322 SIF, 5 min, rt 0.490/0.331 SGF, 3 h, 36-38° C., stirred0.561/0.329 SIF, 3 h, 36-38° C., stirred 4 24.4 1.46 0.15 0.98 1.5 2.50.395/0.323 SGF, 5 min, rt 0.370/0.312 SIF, 5 min, rt 0.416/0.326 SGF, 3h, 36-38° C., stirred 0.533/0.331 SIF, 3 h, 36-38° C., stirred 5 24.41.46 0.15 0.98 2.0 0 0.548/0.334 SGF, 5 min, rt 0.506/0.326 SIF, 5 min,rt 6 24.4 1.46 0.15 0.98 3.0 0 0.355/0.319 SGF, 5 min, rt 0.367/0.315SIF, 5 min, rt 0.485/0.329 SGF, 3 h, 36-38° C., stirred 0.609/0.334 SIF,3 h, 36-38° C., stirred 7 24.4 1.46 0.15 0.98 6.1 0 0.338/0.314 SGF, 5min, rt 0.429/0.337 SIF, 5 min, rt 8 24.4 1.46 0.15 0.98 12.2 00.353/0.317 SGF, 5 min, rt 0.367/0.318 SIF, 5 min, rt 9 24.4 1.46 0.150.98 24.4 0 0.344/0.319 SGF, 5 min, rt 10 24.4 1.46 0.15 0.98 24.4 00.440/0.322 SGF, 70 min, 36-38° C. 0.459/0.324 SIF, 70 min, 36- 38° C.11 24.4 1.46 0.15 0.98 36.6 0 0.346/0.315 SGF, 5 min, rt 0.372/0.317SIF, 5 min, rt 12 23.5 1.41 0.14 0 23.5 0 22.7/8.9  SGF, 5 min, rt

Other salts are also effective in improving re-dispersibility of solidganaxolone particles in simulated gastric and intestinal fluid. Shown intable 22 are test results of sodium citrate.

TABLE 22 Effect of sodium citrate on dispersion of dried ganaxoloneparticles (complexing agent added) in simulated gastric and intestinalfluid (SGF and SIF) Simethicone Methyl- Na D50(μm) No HPMC SLS 30%emulsion paraben Citrate sonication/1 % % % % % min Disperse Entry w/GNXw/GNX w/GNX w/GNX w/GNX sonication conditions 1 24.4 1.46 0.15 0.98 24.40.454/0.333 SGF, 5 min, rt 2 24.4 1.46 0.15 0.98 24.4 0.820/0.337 SGF,70 min, 36-38° C. 3 24.4 1.46 0.15 0.98 24.4 0.982/0.342 SiF, 70 min,36-38° C.

Example 35 Preparation of Solid Ganaxolone Particles Containing Sucrose,Sodium Chloride in Addition to the Milling Excipients

The following was placed in a 25 ml glass scintillation vial: 5.13 mg ofsucrose crystals and 12.5 mg of 25% wt sodium chloride solution.Deionized water (0.5 g) was then added to dissolve the sucrose crystalsand to achieve a homogeneous solution.

Aqueous ganaxolone suspensions (1 g) containing 20.5% ganaxolone, 5.0%HPMC, 0.3% sodium lauryl sulfate, 0.2% methylparaben 0.03% simethicone(30% emulsion in water) (all % w/w) was then added to the vial and themixture was swirled to mix well. The contents in the vial were thenevaporated under reduced pressure (rotary vacuum evaporator at 2-4 mbar)at 70-85° C. until a dry powder was obtained.

The examples listed in Table 23 were prepared in the same fashion withappropriate amounts of each component.

TABLE 23 Milling NaCl solution Deionized water Example Slurry (g) (25%wt) Sucrose (g) (g) 1 1.0 0.3 0 0.5 2 1.0 0.2 0 0.5 3 1.0 0.1 0 0.5 41.0 0.05 0 0.5 5 1.0 0.025 0 0.5 6 1.0 0.0125 0.01025 0.5 7 1.0 0.0164 00.5

Example 36 Effect of Boiling on Ganaxolone Formulations with and withouta Complexing Agent

Approx. 2 g of the milling slurry of Ex-51 and Ex-52 prepared asdescribed in Examples 51 and 52 respectively was placed in a 25 ml glassvial and the vial was closed tightly. The vials were heated in 100° C.oil bath. The particle size of Ex-51 which contained methylparaben ascomplex agent did not change after heating. In contrast, Ex-52 which didnot contain a complexing agent increased its D50 and the increaseappeared to be time dependent. Also, both formulations became moreviscous with Ex-51 becoming a semi-solid (it was diluted with water forparticle size measurement).

TABLE 24 Initial D50 (nm) D50 (nm) before/after 1 min D50 (nm) after 20min after 4 h at Formulation sonication at 100° C. 100° C. Ex-51 320/298326/311 320/310 Ex-52 149/140 246/207 317/302

Example 37 Dispersion Test Results of Solid Ganaxolone ParticleFormulations with Sodium Benzoate as Curing Agent in Simulated Gastricand Intestinal Fluid

Solid ganaxolone particle formulations containing sodiumbenzoate/benzoic acid as a complexing agent were prepared according tothe milling method for formulations with parabens as complexing agent(see method described in Example 52) except using ganaxolone particlesuspension containing 21.25% ganaxolone, 5% HPMC, 0.3% Sodium laurylsulfate, 0.03% simethicone emulsion (30%) with 0.09% sodium benzoate,0.12% citric acid and 0.0093% sodium citrate added post-milling (all %w/w) (Ex-52) and cured for 12 days at the time of use.

As shown in Table 25, solid ganaxolone particles prepared from millingslurry Ex-52 containing 23.5% HPMC, 1.41% SLS and 0.14% simethiconeemulsion (30%) showed poor re-dispersibility. Post-milling addition ofsodium benzoate (0.42%), citric acid (0.56%) and sodium citrate (0.043%)to this suspension improved its re-dispersibility in gastric andintestinal fluid (entry 3). As in the case of paraben-containing solidformulations, addition of sodium chloride (23.5%) further reduced itsD50 upon dispersion in simulated gastric and intestinal fluid (entry 4).

TABLE 25 Simethicone Sodium benzoate/ D50(μm) no HPMC SLS 30% emulsioncitric acid/ NaCl sonication/D50 % % % sodium citrate % (μm) 1 minDispersion Entry w/GNX w/GNX w/GNX % w/GNX w/GNX sonication conditions 123.5 1.41 0.14 0 0 37.2/4.9  SGF, 5 min rt 2 23.5 1.41 0.14 0 23.522.7/8.9  SGF, 5 min, rt 3 23.5 1.41 0.14 0.42/0.56/0.043 0 16.5/0.747SGF, 5 min, rt 14.3/0.525 SIF, 5 min, rt 4 23.5 1.41 0.140.42/0.56/0.043 23.5 9.0/0.347 SGF, 5 min, rt 7.5/0.343 SIF, 5 min, rt

Example 38 Filterability of Ganaxolone Particle Suspensions with andwithout a Complexing Agent (Methylparaben)

Ganaxolone particle suspension (247 mg, Ex-51) containing 20.5%ganaxolone, 5% HPMC, 0.3% sodium lauryl sulfate, 0.2% methylparaben and0.03% simethicone emulsion (30%) was diluted with deionized water (100ml) and thoroughly mixed to obtain 0.5 mg/ml ganaxolone concentration.

Ganaxolone particle suspension (235 mg, Ex-52) containing 21.25%ganaxolone, 5% HPMC, 0.3% sodium lauryl sulfate, 0.03% simethiconeemulsion was diluted with deionized water (100 mL) and thoroughly mixedto obtain 0.5% mg/ml ganaxolone concentration.

The filterability of the diluted suspensions was evaluated bytransmittance (lamp) and particle size change before and afterfiltration. To obtain about 75% transmittance (lamp) before filtration,for dilute suspension of Ex-51, 10 g was mixed with 120 mL of deionizedwater in the Horiba LA-910 sample chamber and the particle size wasmeasured. The chamber was drained and rinsed with water. In the chamberwas then mixed 10 g of the dilute suspension filtered through a 1 micronglass fiber syringe filter and 120 ml deionized water the particle sizewas measured.

For the dilute suspension of Ex-52, 25 g of the suspension and 80 ml ofdeionized water was used. The transmittance (% T lamp) and D50 werecompared before and after filtration to determine the amount ofganaxolone particles retained on the filter. Higher transmittanceindicates lower particle concentration in the measuring chamber.Further, decreasing D50 after filtration indicates the removal ofparticles with altered physical properties (aggregates or adhesion ontothe membrane) during filtration. As data in Table 26 shows, asignificant amount of the ganaxolone particles complexed bymethylparaben were retained by the filter as depicted by the loss oflamp transmittance value which indicates how many particles are in thesample chamber (entry 1). This statement is also consistent withsignificant back pressure encountered during filtration. In contrast,the ganaxolone particles not associated with a complexing agent were notretained by the filter (entry 2). In this case, virtually no backpressure was encountered.

TABLE 26 Filterability of ganaxolone particles with and without acomplexing agent Simethicone Methyl- HPMC SLS emulsion paraben Beforefiltration After filtration % % 30% % D50 % T D50 % T entry (w/GNX)(w/GNX) (w/GNX) (w/GNX) (μm) (lamp) (μm) (lamp) 1 24.4 1.46 0.15 0.980.324 77.5 0.191 94.4 2 23.5 1.41 0.14 0 0.152 77.1 0.146 79.1

Example 37 Milling of Ganaxolone Particles in Aqueous Medium ContainingHPMC and Sodium Lauryl Sulfate (Batch Mode)

Ganaxolone particles in deionized water (180 g) containing a 30 wt %ganaxolone (Marinus Pharmaceuticals Inc., Connecticut, USA), 3 wt %HPMC, and 0.1% (w/w) sodium lauryl sulfate was milled in a DYNO Mill KDL(Willy A. Bachofen A. G., Maschinenfabrik, Basel, Switzerland) with a300 mL glass batch chamber and utilizing 0.1-0.2 mm zirconium oxidebeads (85% of the chamber volume). The milling was conducted for 120 minat a tip speed of 22.5 m/s. The particle size (D50) after milling was106 nm.

Example 38 Milling of Aqueous Ganaxolone Dispersion Containing HPMC(Continuous Mode)

Powdered ganaxolone aqueous dispersion (1200 g) comprising a mixture of20 wt % ganaxolone and 3 wt % HPMC was milled in a DYNO Mill KDL with a600 mL SiC lined continuous chamber and 0.4 mm yttrium stabilizedzirconium oxide beads (88% volume loading). The milling slurry wasre-circulated via a peristaltic pump (250 mL/min) through a jacketedstainless steel holding tank chilled between 0-12° C. The tip speed was10 m/s. The product temperature at the outlet was kept below 45° C. Theprogress of the milling run was followed by particle size measurement(D50) at various time points. After 2 hours of milling, the slurry witha D50 of 330 nm was filtered through a 10 μm cartridge and storedrefrigerated.

Example 39 Milling of Aqueous Ganaxolone Dispersion Containing HPMC(Continuous Mode)

Powdered ganaxolone aqueous dispersion (1000 g) comprising a mixture of15 wt % ganaxolone and 2.5 wt % HPMC was milled in a DYNO Mill KDL asdescribed for Example 38. After 70 min residence time, D50 was 125 nm.The slurry was split into 6 portions (Ex-39A-F) and different excipientswere added to each portion. The final amounts of the excipients of eachformulation are listed in the Table 27.

TABLE 27 Formulation A B C D E F HPMC % 2.5 2.5 2.5 5.0 2.5 7.5 (w/w)SLS % 0 0 0.3 0.1 0 0.3 (w/w) DOSS % 0 0 0 0 0.1 0 (w/w)

Example 40 Milling of Ganaxolone Particles in Aqueous Medium ContainingHPMC and Sodium Lauryl Sulfate (Continuous Mode)

Ganaxolone particles in deionized water (1200 g) containing 15 wt %ganaxolone, 3 wt % HPMC, and 0.05 wt % Sodium lauryl sulfate was milledin a DYNO Mill KDL with a 600 mL SiC lined continuous chamber and 0.4 mmyttrium stabilized zirconium oxide beads (90% volume loading). Themilling slurry was re-circulated via a peristaltic pump (250 mL/min)through a jacketed stainless steel holding tank chilled between 0-12° C.The tip speed was 10 m/s. The product temperature at the outlet was keptbelow 45° C. About 15 min into the milling, additional 0.05% SLS wasadded as a concentrated solution. The progress of the milling run wasfollowed by particle size measurement (D50) at various residence timepoints (plot shown in FIG. 4). After milling, the slurry was filteredthrough a 10 μm cartridge and stored refrigerated. Residence times ofapproximately 30 minutes or more produced sub-micron ganaxoloneparticles having D50 of 100 nm to 150 nm.

Example 41 Milling of Ganaxolone Particles in Aqueous Medium ContainingHPMC, Sodium Lauryl Sulfate, Polyvinyl Alcohol, Methylparaben andPropylparaben (Continuous Mode)

Ganaxolone particles in deionized water (1000 g) containing 15 wt %ganaxolone, 3 wt % HPMC, 1 wt % polyvinyl alcohol, 0.1 wt %methylparaben, 0.02 wt %, and propylparaben was milled in a DYNO MillKDL with a 600 mL SiC lined continuous chamber and 0.4 mm yttriumstabilized zirconium oxide beads (90% volume bead loading). The millingwas conducted according to the method described in Example 38. Duringthe milling, two portions of 0.025% (w/w) of sodium lauryl sulfate wereadded as a concentrate solution. After 72.9 min of residence time, theD50 was 153 nm. The milling slurry was split into three containers,additional sodium lauryl sulfate was added to two of the containers sothat the total SLS levels reached 0.1 and 0.2% w/w respectively. Theslurries were stored at ambient temperature and particle size becamefully sable after 6 days (D50 values: 205, 188 and 193 respectively).

Example 42 Milling of Ganaxolone Particles in Aqueous Medium ContainingHPMC, Sodium Lauryl Sulfate, Polyvinyl Alcohol, Methylparaben,Propylparaben and Simethicone (Continuous Mode)

Ganaxolone particles in deionized water (1200 g) containing 25 wt %ganaxolone, 5 wt % HPMC, 1 wt % polyvinyl alcohol, 0.1 wt % sodiumlauryl sulfate, 0.1 wt % methylparaben, 0.02 wt % propylparaben, and 0.1wt % simethicone in deionized water was milled in a DYNO Mill KDL with a600 mL SiC lined continuous chamber and 0.4 mm yttrium stabilizedzirconium oxide beads (90% volume bead loading). The milling wasconducted according to the method described in Example 38. After 27.5min of residence time, the D50 was 180 nm. The milling slurry wasfiltered through a 10 μm cartridge and diluted (2×) with diluent 5%(w/w) HMPC, 1% (w/w) polyvinyl alcohol, 0.1% (w/w) sodium laurylsulfate, 0.1% (w/w) methylparaben and 0.02% (w/w) propylparaben and 0.1%(w/w) simethicone and stored at ambient temperature for particle size tostabilize. The D50 became 327 nm after the particles were fully cured.

Example 43 Milling of Ganaxolone Particles in Aqueous Medium ContainingHPMC, Sodium Lauryl Sulfate, Polyvinyl Alcohol, Sodium Benzoate, CitricAcid and Sodium Citrate (Continuous Mode)

Ganaxolone particles in deionized water (1200 g) containing 25 wt %ganaxolone, 5 wt % HPMC, 1 wt % polyvinyl alcohol, 0.1 wt % sodiumbenzoate, 0.12 wt % citric acid, 0.1 wt % sodium lauryl sulfate, 0.0093wt % sodium citrate, and 0.025 wt % simethicone was milled in a DYNOMill KDL with a 600 mL SiC lined continuous chamber and 0.4 mm yttriumstabilized zirconium oxide beads (90% volume bead loading). The millingwas conducted in the same fashion as described in Example 38. After 25.0min of residence time, the D50 was 160 nm. The milling slurry wasfiltered through a 10 μm cartridge and stored at ambient temperature.Its particle size (D50) became 361 nm after 4 weeks.

Example 44 Milling of Ganaxolone Particles in Aqueous Medium ContainingHPMC, Sodium Lauryl Sulfate, Polyvinyl Alcohol, Methylparaben andPropylparaben (Continuous Mode)

Ganaxolone particles in deionized water (1200 g) containing 25 wt %ganaxolone, 3 wt % HPMC, 1 wt % polyvinyl alcohol, 0.1 wt % sodiumlauryl sulfate, 0.1 wt % methylparaben and 0.02 wt % propylparaben wasmilled in a DYNO Mill KDL with a 600 mL SiC lined continuous chamber and0.4 mm yttrium stabilized zirconium oxide beads (90% volume beadloading). The milling was conducted according to the method described inExample 43. After 25.4 min of residence time, the D50 was 162 nm. Themilling slurry was filtered through a 10 μm cartridge and diluted (2×)with diluent containing 7.5% (w/w) HMPC, 1% (w/w) polyvinyl alcohol,0.1% 9w/w) sodium lauryl sulfate, 0.1% (w/w) methylparaben and 0.02%(w/w) propylparaben in water to obtain a liquid dispersion. Thedispersion was stored at ambient temperature for particle size tostabilize. The D50 was 306 nm after 2 days and 380 nm in 4 weeks.Additional additives, for example flavoring agent and a sweetener, canbe added to the liquid dispersion either before or after curing toobtain the final ganaxolone particle formulation.

Example 45 Re-Milling of Aqueous Ganaxolone Slurry Containing HPMC,Sodium Lauryl Sulfate, Polyvinyl Alcohol, Methylparaben, andPropylparaben (Continuous Mode)

The final milling slurry obtained in Example 44 was re-milled two dayslater according to the method described in Example 44 for 69 min ofresidence time. The D50 was 164 nm. It became 200 nm in 7 to 10 days andremained the same when tested 6 months later.

Example 46 Milling of Aqueous Ganaxolone Dispersion Containing HPMC(Continuous Mode)

Powdered ganaxolone aqueous dispersion (1200 g) comprising a mixture of15 wt % ganaxolone and 3 wt % HPMC was milled in a DYNO Mill KDL asdescribed for Example 38. During milling, 2 portions of 0.05% w/w sodiumlauryl sulfate were added to keep the milling slurry fluid. After 50.8minutes of residence time, D50 was 116 nm.

Example 47 Milling of Aqueous Ganaxolone Dispersion Containing HPMC,Sodium Lauryl Sulfate and Simethicone (Continuous Mode)

Powdered ganaxolone aqueous dispersion (1200 g) comprising a mixture of30 wt % ganaxolone and 5 wt % HPMC, 0.2 wt % sodium lauryl sulfate and100 ppm simethicone was milled in a DYNO Mill KDL as described forExample 38. After 24.0 minutes of residence time, D50 was 163 nm.

Example 48 Milling of Aqueous Ganaxolone Dispersion Containing HPMC,Sodium Lauryl Sulfate and Simethicone (Continuous Mode)

Powdered ganaxolone aqueous dispersion (1200 g) comprising a mixture of25 wt % ganaxolone and 5 wt % HPMC, 0.3 wt % sodium lauryl sulfate and100 ppm simethicone was milled in a DYNO Mill KDL as described forExample 38. After 67.7 minutes of residence time, D50 was 145 nm.

Example 49 Milling of Aqueous Ganaxolone Dispersion Containing HPMC,Sodium Lauryl Sulfate and Simethicone (Continuous Mode)

Powdered ganaxolone aqueous dispersion (1500 g) comprising a mixture of25 wt % ganaxolone and 5 wt % HPMC, 0.1 wt % sodium lauryl sulfate and0.028% simethicone 30% emulsion was milled in a DYNO Mill KDL asdescribed for Example 38, except the tip speed was 15 m/s. After 39minutes of residence time, D50 was 113 nm.

Example 50 Milling of Aqueous Ganaxolone Dispersion Containing HPMC,Sodium Lauryl Sulfate and Simethicone (Continuous Mode)

Three additional milling runs were performed in the same fashion asdescribed for Example 46 except on larger scales. The residence time was33, 35, and 34 minutes respectively and at the end of milling, the D50was 143, 139, and 155 nm (after 1 minute sonication) respectively. Themilled slurries from these runs were diluted in a two-step fashion asdescribed in Example 21 to 50 mg/mL ganaxolone formulations withappropriate levels of excipients such as HPMC, PVA and SLS and otherdesirable components such as preservatives, sweetener and artificialflavors. The D50 values of the 50 mg/mL formulations were 320, 295, and315 nm respectively.

Example 51 Milling of Aqueous Ganaxolone Dispersion with ComplexingAgent for Solid Dosage Form

Ganaxolone was wet milled in a 600 ml chamber using a DYNO-Mill KDLequipped with four 64 mm polyurethane agitator discs. The mill wasoperated at 3000 RPM or a tip speed of 10 m/sec. The mill was loadedwith 88 vol % of 0.4 mm yttrium stabilized zirconium oxide beads. Themilling slurry (1200 gm) contained 25 wt % ganaxolone, 5 wt %hydroxypropyl methylcellulose (Pharmacoat 603), 0.0333 wt % 30%simethicone emulsion, 0.3 wt % sodium lauryl sulfate and 0.2 wt %methylparaben. This slurry was circulated through the mill via aperistaltic pump and returned to a cooled reservoir where it wasre-circulated through the mill. The mill was operated in thisrecirculation mode, keeping the slurry temperature at 35-40° C., for atotal of 410 minutes. Using a free or void volume of 262 ml in the mill,a residence time of 90 minutes was calculated. The product slurry wasfiltered through a 20 micron polypropylene cartridge filter to give 1185g of milled ganaxolone slurry. The particle size (D50) measured on aHoriba LA 910 was 164 nm without sonication/153 nm with 1 min.sonication at low power. After 7 days the particle size increased to 320nm/309 nm sonicated. The D50 did not change after this curing period forthe duration of all other studies conducted with this formulation.

Example 52 Milling of Aqueous Ganaxolone Dispersion without ComplexingAgent for Solid Dosage Form

Ganaxolone was wet milled in a 600 ml chamber using a DYNO-Mill KDLequipped with four 64 mm polyurethane agitator discs. The mill wasoperated at 4000 RPM or a tip speed of 15 m/sec. The mill was loadedwith 88 vol % of 0.4 mm yttrium stabilized zirconium oxide beads. Themilling slurry (1200 gm) contained 25 wt % ganaxolone, 5 wt %hydroxypropylmethyl cellulose (Pharmacoat 603), 0.3% sodium laurylsulfate and 0.033 wt % simethicone emulsion (30% in water, Dow CorningQ7-2587). This slurry was circulated through the mill via a peristalticpump and returned to a cooled reservoir where it was re-circulatedthrough the mill. The mill was operated in this recirculation mode,keeping the slurry temperature at 40 to 50° C., for a total of 340minutes. Using a free or void volume of 262 ml in the mill, a residencetime of 75 min. is calculated. The product slurry was filtered through a20 micron polypropylene cartridge filter to give 1271 gm of milledganaxolone slurry. The particle size (D50) measured on a Horiba LA 910was 103 nm/102 nm sonicated. After 7 days the particle size increasedslightly to 136 nm/112 nm sonicated.

Example 53 Immediate Release Ganaxolone 300 Mg Capsules with and withoutComplexing Agent

Suspensions (1200 grams) in water containing 25 wt % ganaxolone, 5.0% wt% hydroxypropyl methylcellulose (Pharmacoat 603), 0.0333 wt % of 30%simethicone emulsion, and 0.2 wt % sodium lauryl sulfate, either with0.05 wt % methylparaben (capsule Ex. 1) or with no methylparaben(capsule Ex. 2, 5.2 wt % of HPMC instead of 5 wt %) are prepared. Eachwt % is based on the total weight of the suspension.

The ganaxolone particles are milled using conditions as described inExample 51. For formulations with complexing agent (Capsule Form 1),ganaxolone nanoparticles having a particle size (D50) of about 120 nm asmeasured by Horiba LA 910 particle size analyzer are obtainedimmediately after milling. This volume-weighted-median particle sizegrows to about 220 nm after 7 days of curing at ambient temperature,indicating that ganaxolone complex is formed. The D50 does not changeafter this curing period for the duration of the study. For Capsule Form2 (without complexing agent), ganaxolone nanoparticles having the sameparticle size (D50) (about 120 nm) are obtained immediately aftermilling.

Sucrose (48.5 g) and NaCl (6.5 g) (together about 13 wt % of solids) andwater (800 ml) is added to each of the ganaxolone suspensions forCapsule Form 1 and 2 and the resulting mixtures are homogenized for 20minutes for spray drying. The compositions of the mixtures to be spraydried are given in Table 28.

TABLE 28 Composition of spray mixture prior to spray layering CapsuleExample 1 Ganaxolone Capsule Example 2 Complex Ganaxolone Wt %/ (NoParaben) Weight, total solid Weight, Wt % based on Component gram wt, %gram total solid weight, % Ganaxolone 300 71.7 300 71.4 HPMC 60 14.362.4 14.9 Simethicone 0.12 0.03 0.12 0.03 SLS 2.4 0.57 2.4 0.57Methylparaben 0.60 0.14 0 0 Sucrose 48.5 11.6 48.5 11.5 Sodium 6.5 1.66.5 1.5 chloride Total 418.12 100 419.92 100

For each of Capsule Form 1 and 2, 100 grams of microcrystallinecellulose (MCC) beads (e.g. Celsphere, 30/35 mesh) are added to a GlattGPCG-3 fluidized bed with Wurster column insert (4 inch), inlettemperature of about 55° C. and air temp of about 40° C. (total airvolume approx. 175 cubic cm/hr). About 2000 grams of each spray mixtureare sprayed (bottom spray) through 1.2 mm nozzles at 11 mls/min and 1.5bar of pressure until a layering of about 400 wt % is achieved ascompared to initial beads weight. The theoretical compositions of thespray layered ganaxolone complex particles (Capsule Form 1) andganaxolone particles (Capsule Form 2) are shown in Table B. Actual Spraylayering yields have been >90% theoretical for both form 1 and 2.

TABLE 29 Composition of spray layered particles after spray dryingCapsule Form 2 Capsule Form 1 Ganaxolone (No Methyl Ganaxolone ComplexParaben) Weight, Wt %/total Weight, Wt % based on Component gram solidwt, % gram total solid weight, % Ganaxolone 300 57.9 300 57.7 HPMC 6011.6 62.4 12.0 Simethicone 0.12 0.02 0.12 0.02 SLS 2.4 0.46 2.4 0.46Methylparaben 0.60 0.12 0 0 Sucrose 48.5 9.4 48.5 9.3 NaCl 6.5 1.25 6.51.25 MCC beads 100 19.3 100 19.2 Total 518.12 100 519.92 100

The spray layered ganaxolone complex particles (Capsule Form 1) organaxolone particles (Capsule Form 2) are then filled into gelatincapsules with a fill weight of 518-520 mg coated beads to achieve a 300mg dose.

Examples 54 Delayed Release Ganaxolone 300 Mg Capsules (with and withoutComplexing Agent)

Ganaxolone containing immediate release beads (500 g, Capsule Form 1) organaxolone multiparticulates (500 g, Capsule Form 2) prepared asdescribed in Example 53 and as shown in Table 30 are loaded directlyinto a rotary granulator/coater (Freund CF-360 granulator) for entericcoating. The rotating particle bed is sprayed with a coating solutioncontaining 50 wt % Eudragit® L 30-D55, 2.5 wt % talc, 1.5 wt % dibutylsebecate, 20 wt % ethanol, 23.5 wt % isopropyl alcohol, and 2.5 wt %water. A coating level of about 8 wt % is achieved. The ganaxolonecontent in each coated bead is about 53.4 wt % based on the total weightof the coated beads.

About 295 mg of uncoated capsule Form 1 or 2 and 240 mg coated beadsfrom capsule Form 1 or 2 thus obtained are hand-filled into gelatincapsule shells, respectively, to form modified release ganaxolonecomplex 300 mg capsules (Capsule Form 3) or ganaxolone 300 mg modifiedrelease capsules without methylparaben (Capsule Form 4). Theseparticulates are substantially insoluble in the stomach due to theenteric coating but substantially soluble in the intestine. The totalcapsule fill weight is 565 mg.

Example 55 Pulsatile Release Ganaxolone 300 Mg Capsules (with andwithout Complexing Agent)

For Capsule Form 5, uncoated ganaxolone beads obtained for Capsule Form1 and as described in Table 29 are mixed with coated ganaxolone obtainedfor Capsule Form 3 (Example 54) at a 60 wt % to 40 wt % ratio to obtaina mixture. About 540 mg of the blended mixture is hand-filled in a hardgelatin capsule to obtain a pulsatile ganaxolone complex 300 mg capsule.

Similarly, for Capsule Form 6, uncoated ganaxolone multiparticulatesobtained for Capsule Form 2 and as described in Table 29 are mixed withcoated ganaxolone multiparticulates obtained for Capsule Form 4 at a 40wt % to 60 wt % ratio to obtain a mixture. The ganaxolone content in themixture is about 55.5 wt %. About 540 mg of the blended mixture isfilled in a gelatin capsule to obtain a pulsatile ganaxolone 300 mgcapsule (without complexing agent).

Examples 56 Ganaxolone 300 Mg Capsules in Swelling Plug Devices (withand without Complexing Agent)

About 520 mg of the beads obtained above in Example 53, Capsule Forms 1and 2, are hand-filled into a swelling plug device as describedpreviously. The half-capsule shell is made from apoly(methylmethacrylate) material which does not dissolve in thestomach. The open end of the capsule shell is plugged with a cylindricalplug formed from a co-poly(alkylene oxide) crosslinked by reaction withunsaturated cyclic ether group. The plugged capsule half is finallysealed with a water-soluble gelatin to obtain ganaxolone complex 300 mgcapsule (Capsule Form 7) and ganaxolone 300 mg capsule (without methylparaben) (Capsule Form 8).

Example 57 Delayed Release Ganaxolone 300 Mg Capsules in Swelling PlugDevices (with and without Complexing Agent)

The sealed devices obtained in Example 56, with and without complexingagent, are further coated with an enteric coating to obtain delayedrelease ganaxolone complex 300 mg device (Capsule Form 9) and ganaxolone300 mg device (without methylparaben) (Capsule Form 10). For example,the sealed devices are coated in a Hi-Coater (Vector Corp., Marion,Iowa, USA) with a coating solution containing 50 wt % Eudragit® L30-D55, 2.5 wt % talc, 1.5 wt % dibutyl sebecate, 20 wt % ethanol, 23.5wt % isopropyl alcohol, and 2.5 wt % water. A coating level of about 10wt % is achieved. The coated devices are substantially insoluble in thestomach but substantially release all ganaxolone in the intestine

Example 58 Pulsatile Release Ganaxolone Tablets Containing a ModifiedRelease Inner Core and an Immediate Release Coating

The following is the process for preparing pulsatile release ganaxolonetablets in accordance with the invention. In this formulation therelative amounts of water-soluble film-forming substance(polyvinylpyrrolidone) and water-insoluble film-forming substance(ethylcellulose) in the second coat of the encapsulated pellets are inthe ratio of 1:20.

Ganaxolone particle suspension formulation (12.6% ganaxolone, 2.6% HPMC,0.026% SLS, 0.018% simethicone emulsion (30% simethicone in water), 0.3%sodium chloride and 2.4% sucrose is dried by rotary evaporation andspray layered onto sucrose beads. The spray layered form is prepared byevaporating the layering slurry onto sugar beads (Paulaur 30/35 mesh)through a fluidized bed coating process yielding approximately 60%ganaxolone loading (% wt GNX/% total bead wt).

The resulting spray layered beads are dried (40° C., 5-10 hr.) andscreened, first through a 12-mesh screen to remove aggregates and thenover a 20-mesh screen to remove fines.

The ganaxolone containing beads (25 kg) are tumbled in a coating pan andsimultaneously dusted with talc (USP, 1.28 kg.) containing blue dye (FD& C Blue No. 1 Lake Dye, 0.0129 kg.) and sprayed with a solution ofpolyvinylpyrrolidone (0.0570 kg.) and ethylcellulose (50 c.p.s., 1.14kg.) in ethanol (alcohol, 95%, 27.3 kg). The second coat as thusconstituted consists of 2% water-soluble film-forming substance, 46%water-insoluble film forming substance and 52% dusting powder. Theresulting encapsulated beads are dried (40° C.) to a moisture contentbetween 0.6% and 1.0% and screened successively through 12-mesh and20-mesh screens. The encapsulated beads as thus constituted of sugarbeads, ganaxolone particles as first coat and PVP, ethylcellulose secondcoat.

A mixture of anhydrous lactose (4 kg.), microcrystalline cellulose (5.14kg.), ethylcellulose (50 c.p.s., 2.8 kg.) and hydrogenated vegetable oil(1.19 kg.) is milled, and blended with 25 kg of encapsulated ganaxolonebeads. The resulting blend is compressed into tablets, each weighing 700mg and each containing 300 mg of ganaxolone. The tableting mixture asthus constituted consists of 17.5% diluent, 22.7% diluent-binder, 12%binder and 5.22% hydrophobic lubricant and 42.5% ganaxolone. The tabletsas thus constituted consist of encapsulated beads and tableting mixture.

Example 59 Enterically Coated Ganaxolone Tablets

Ganaxolone particle suspension formulation Ex-52 after curing for 7 dayswith the addition of 0.05% methylparaben is prepared as a spraygranulate containing sucrose (3%) and sodium chloride (1.5%). Theresulting granulate is dried (40° C., 5-hr.) and screened, first througha 12-mesh screen to remove aggregates and then over a 20-mesh screen toremove fines.

Prosolv 90, Ganaxolone spray granulate, and Dipotassium PhosphatePowder, are added sequentially into a Bohle Bin Blender (BL07C,Warminster, Pa., USA) and blended for 10±0.1 minutes at 11±1 rpm.Additional Prosolv 90 and Sodium Starch Glycolate are added and blendedfor 10±0.1 minutes at 11±1 rpm. The material is then milled and thenpassed through a 0.5 mm screen (35 Mesh).

Blend Component Weight % w/w Silicified Microcrystalline Cellulose, NF4.255 kg 37.0 (Prosolv 90) Sodium Starch Glycolate, NF, EP 0.230 kg 2.00Sodium Chloride 0.287 kg 2.5 Magnesium Stearate 0.0575 kg  0.5Dipotassium Phosphate Powder, USP, PE 0.230 kg 2.00 Ganaxolone spraygranulate  6.44 kg 56.0 Totals  11.5 kg 100.0

The Ganaxolone Blend is loaded into a tablet compressing machine, suchas a Fette 1200 B Tool Tablet Press (TP06) or equivalent, and tabletsare formed using oval upper and lower punches. Tablets are obtainedhaving an average core tablet weight of 750.0 mg (containing approx. 300mg ganaxolone) with average acceptable upper and lower tablet weightlimits of ±5.0%.

Friability is determined by Current USP <1216> at the beginning and endof each compression run and is NMT 0.5%. Disintegration times aredetermined using Current USP <701> at the beginning and end of eachcompression batch. Disintegration time is NMT 5 minutes.

An enteric coat is applied to the tablet cores as follows: The entericcoating comprising Opadry® Enteric from Colorcon® and the over coatcomprising Opadry® clear applied sequentially as aqueous coatingsuspensions using a coating pan. The tablet cores are preheated to 46°C. (Exhaust air temperature). The pan speed is adjusted to provideadequate tablet flow and the coating suspensions are sprayed onto thetablets at an atomizing air pressure of 18-30 psi; an inlet airtemperature of 60-70° C. for over coat, and of 42-50° C. for the entericcoat; an exhaust air temperature of 40 to 50° C. for the over coat and30 to 35° C. for the enteric coat; a spray rate of 15 to 50 ml/min.; andan inlet air flow of 175 to 300 CFM. One of skill in the art willunderstand that the processing parameters for coating are dependent inpart upon the size of the batch to be coated and can be adjustedaccordingly. The enteric coating should be applied so that a tablet coreweight gain of 8-15% w %/tablet core weight is achieved. Celluloseacetate phthalate, hydroxypropyl methylcellulose phthalate, polyvinylacetate phthalate, a methacrylic acid copolymer, hydroxypropylmethylcellulose acetate succinate, shellac, cellulose acetatetrimellitate, or a combination comprising one or more of the foregoingenteric polymers may be used in place of the Opadry Enteric coating.

Example 60 Ganaxolone Immediate Release Tablet

Ganaxalone tablet core are prepared as described above in Example 59.Over coat comprising Opadry® clear is applied as an aqueous coatingsuspensions using a coating pan. The tablet cores are preheated to 46°C. (Exhaust air temperature). The pan speed is adjusted to provideadequate tablet flow and the coating suspensions are sprayed onto thetablets at an atomizing air pressure of 18-30 psi; an inlet airtemperature of 60-70° C., an exhaust air temperature of 40 to 50° C., aspray rate of 15 to 50 ml/min.; and an inlet air flow of 175 to 300 CFM.A color coating such as Colorcon Opaspray or Opalux may be applied priorto the final application of Opadry clear to provide a colored tablet.

Example 62 Enterically Coated Ganaxolone Tablets Containing Sugar Beads

Ganaxolone particle suspension formulation with or without complexingagent is prepared as a described in Examples 52 (Ex-52A, containing0.05% methylparaben and cured for 7 days) and 52 (Ex-52, no complexingagent). To each of these compositions is added sucrose (3%) and sodiumchloride (1.5%). Sufficient water is added as in Example 53 to make adispersion containing about 18% solid content.

For each of the particle suspensions 100 grams of sugar beads (e.g.Paulaur 30/35 mesh) are added to a Glatt GPCG-3 fluidized bed withWurster column insert (4 inch), inlet temperature of about 55° C. andair temp of about 40° C. (total air volume approx. 175 cubic cm/hr).About 2000 grams of each spray mixture are sprayed (bottom spray)through 1.2 mm nozzles at 10 mls/min and 1.5 bar of pressure until alayering of about 400 wt % is achieved as compared to initial sugarbeads weight. The compositions of the spray layered ganaxolone particleson a sugar bead containing 60% Ganaxolone or ganaxolone complexparticles by total bead weight is achieved. Lactose monohydrate,ganaxolone beads, and dipotassium phosphate powder, are addedsequentially into a Bohle Bin Blender (BL07C, Warminster, Pa., USA) andblended for 10±0.1 minutes at 11±1 rpm. Additional Prosolv 90 and sodiumstarch glycolate are added and blended for 10±0.1 minutes at 11±1 rpm.The material is then milled and then passed through a 0.5 mm screen (35Mesh).

Blend Component Weight % w/w Lactose monohydrate 3.128 kg 27.2 SodiumStarch Glycolate, NF, EP 0.230 kg 2.00 Sodium Chloride 0.287 kg 2.5Magnesium Stearate 0.0575 kg  0.5 Dipotassium Phosphate Powder, 0.230 kg2.00 USP, PE Ganaxolone spray layered beads 7.567 kg 65.8 Totals  11.5kg 100.0

The Ganaxolone Blend is loaded into a tablet compressing machine, suchas a Fette 1200 B Tool Tablet Press (TP06) or equivalent, and tabletsare formed using oval upper and lower punches. Tablets are obtainedhaving an average core tablet weight of 790 mg (containing 300 mgganaxolone) with average acceptable upper and lower tablet weight limitsoff 5.0%.

Friability are disintegration times are as described in Example 59.

An enteric coat is applied to the tablet cores as follows: The entericcoating comprising Opadry® Enteric from Colorcon® and the over coatcomprising Opadry® clear applied sequentially as aqueous coatingsuspensions using a coating pan. The tablet cores are preheated to 46°C. (Exhaust air temperature). The pan speed is adjusted to provideadequate tablet flow and the coating suspensions are sprayed onto thetablets at an atomizing air pressure of 18-30 psi; an inlet airtemperature of 60-70° C. for over coat, and of 42-50° C. for the entericcoat; an exhaust air temperature of 40 to 50° C. for the over coat and30 to 35° C. for the enteric coat; a spray rate of 15 to 50 ml/min.; andan inlet air flow of 175 to 300 CFM. One of skill in the art willunderstand that the processing parameters for coating are dependent inpart upon the size of the batch to be coated and can be adjustedaccordingly. The enteric coating should be applied so that a tablet coreweight gain of 8-15% w %/tablet core weight is achieved. Celluloseacetate phthalate, hydroxypropyl methylcellulose phthalate, polyvinylacetate phthalate, a methacrylic acid copolymer, hydroxypropylmethylcellulose acetate succinate, shellac, cellulose acetatetrimellitate, or a combination comprising one or more of the foregoingenteric polymers may be used in place of the Opadry Enteric coating.

Example 63 Pharmacokinetic Analysis of 200 Mg of Ganaxolone ComplexSuspension (50 mg/Ml) Containing Pva Administered in 6 HealthyVolunteers in the Fasted State

Following an overnight fast of at least 10 hours, 6 healthy subjectswere administered ganaxolone (4 ml of a 50 mg/ml suspension manufacturedas in example 50 as the ganaxolone complexed composition) with 240 mL (8fluid ounces) of water. No food allowed for at least 4 hours post-dose.Water was allowed as desired except for one hour before and after drugadministration. Other oral fluids (juices, coffee, carbonated beveragesetc.) were not permitted from 4 hours pre-dose to 4 hours post-dose.Grapefruits or grapefruit juice intake was prohibited during the entirestudy. A standardized meal was provided at 4 hours post-dose.

Blood samples (4 ml) for PK analysis were collected at 0.5, 1, 1.5, 2,3, 4, 6, 8, and 12 hours following dosing using dipotassium EDTA as theanti-coagulant. Plasma was generated by centrifugation at around 4-8kRPM for 15 minutes at 0° C., frozen below −20° C. for storage andshipping and analyzed using a validated HPLC/MS/MS/MS method with an LOQof 1 ng/ml. Results yielded a mean Cmax of 37±25 ng/ml and an AUC₍₀₋₂₄₎of 184±104 ng*h/ml.

Example 64 Effect of Freeze/Thaw Cycles on the Stability of GanaxoloneFormulations with and without a Complexing Agent

Ganaxolone formulations Ex-51 and Ex-52 (with and without complexingagent as described in Examples 51 and 52 respectively), were tested forfreeze thaw stability as follows:

10 gm of each formulation was placed into a 25 ml HDPE scintillationvial with HDPE cap. These were placed into a 500 ml glass beakercontaining approx. 1 inch of Styrofoam packing (to slow freezingprocess) and placed into an insulated carton containing crushed dry ice.The vials were stored overnight and then thawed at room temperature for1 hour. This process was repeated for the same vials 2× comprising 3freeze/thaw cycles. The particle size for each formulation was measuredby the method already described and compared to control material storedat room temperature in the same container closure system.

TABLE 30 Particle size (D50) before and after freezing/thaw cycles forganaxolone particles with and without a complexing agent (methylparaben)Initial D50 (nm) D50 (nm) after 3 freeze/thaw Before/after 1 min cyclesFormulation sonication Before/after 1 min sonication Ex-51 320/298319/310 Ex-52 149/140 822/341

We claim:
 1. A method of treating human patients in need of treatmentfor a central nervous system disorder selected from the group consistingof epileptic seizures, infantile spasms, anxiety, stress, panic,depression, postpartum depression, insomnia, premenstrual syndrome,post-traumatic stress disorder, substance abuse withdrawal,hypertension, pain, migraine headache, headache associated with pre- andperi-menstrual period, Neimann Pick disease Type-C and Mucolipidosistype IV lipid accumulation, mucolipidosis Type IV lipid accumulation,AIDS-related dementia, Alzheimer's disease, Huntington's disease, andParkinson's disease, comprising administering an effective amount ofsolid stabilized particles comprising ganaxolone, a hydrophilic polymer,a wetting agent, and an effective amount of a complexing agent which isa small organic molecule having a molecular weight less than 550 andcontaining a moiety selected from the group consisting of a phenolmoiety, an aromatic ester moiety and an aromatic acid moiety, whereinthe stabilized particles have a volume weighted median diameter (D50) ofthe particles is from about 50 nm to about 500 nm and the concentrationof ganaxolone in the solid stabilized particles is at least 50% byweight.
 2. The method of claim 1, wherein the hydrophilic polymer is inan amount from about 3% to about 50%, w/w, based on the weight of thesolid particles.
 3. The method of claim 2, wherein the wetting agent isin an amount from about 0.01% to about 10%, w/w, based on the weight ofthe solid particles.
 4. The method of claim 2, wherein the stabilizedparticles exhibit an increase in volume weighted median diameter (D50)of not more than about 150% when the particles are dispersed insimulated gastric fluid (SGF) or simulated intestinal fluid (SIF) at aconcentration of 0.5 to 1 mg ganaxolone/mL and placed in a heated bathat 36° to 38° C. for 1 hour as compared to the D50 of the stabilizedparticles when the particles are dispersed in distilled water under thesame conditions, wherein the volume weighted median diameter (D50) ofthe stabilized particles dispersed in SGF or SIF is less than about 750nm.
 5. The method of claim 1, wherein the stabilized particles exhibitan increase in volume weighted median diameter (D50) of not more thanabout 150% when the formulation is dispersed in 15 mL of SGF or SIF at aconcentration of 0.5 to 1 mg ganaxolone/mL as compared to the D50 of thestabilized particles when the particles are dispersed in distilled waterunder the same conditions, wherein the volume weighted median diameter(D50) of the stabilized particles dispersed in SGF or SIF is less thanabout 750 nm.
 6. The method of claim 1, wherein the ganaxolone ispresent in an amount greater than 50% to about 80%, based on the weightof the particles.
 7. The method of claim 6, wherein the stabilizedparticles exhibit an increase in volume weighted median diameter (D50)of not more than about 150% when the particles are dispersed insimulated gastric fluid (SGF) or simulated intestinal fluid (SIF) at aconcentration of 0.5 to 1 mg ganaxolone/mL and placed in a heated bathat 36° to 38° C. for 1 hour, as compared to the D50 of the stabilizedparticles when the particles are dispersed in distilled water under thesame conditions, wherein the volume weighted median diameter (D50) ofthe stabilized particles dispersed in SGF or SIF is less than about 750nm.
 8. The method of claim 1 in the form of a powder.
 9. The method ofclaim 1, wherein the particles are incorporated into a dosage formselected from the group consisting of a tablet or capsule.
 10. Themethod of claim 1, wherein the volume weighted median diameter (D50) ofthe stabilized particles dispersed in distilled water is from about 100nm to about 350 nm.
 11. The method of claim 1, wherein the complexingagent is selected from the group consisting of parabens, benzoic acid,methyl anthranilate, and pharmaceutically acceptable salts thereof andmixtures thereof.
 12. The method of claim 1, wherein the paraben isselected from the group consisting of methylparaben, ethylparaben,propylparaben, pharmaceutically acceptable salts thereof and mixturesthereof.
 13. The method of claim 1, wherein the hydrophilic polymer isselected from the group consisting of a cellulosic polymer, a vinylpolymer and mixtures thereof.
 14. The method of claim 13, wherein thecellulosic polymer is a cellulose ether.
 15. The method of claim 13,wherein the cellulose ether is hydroxypropymethylcellulose.
 16. Themethod of claim 13, wherein the vinyl polymer is polyvinyl alcohol. 17.The method of claim 1, wherein the wetting agent is selected from thegroup consisting of sodium lauryl sulfate, a pharmaceutically acceptablesalt of docusate, and mixtures thereof.
 18. The method of claim 1,wherein the particles are incorporated into a solid dosage form, furthercomprising at least one pharmaceutically acceptable excipient selectedfrom the group consisting of an ionic dispersion modulator, an watersoluble spacer, a disintegrant, a binder, a surfactant, a plasticizer, alubricant, and any combinations or mixtures thereof.
 19. The method ofclaim 18, wherein the pharmaceutically acceptable excipient comprises anionic dispersion modulator.
 20. The method of claim 19, wherein theionic dispersion modulator is in an amount from about 1% to about 50%,w/w, based on the weight of the solid particles.
 21. The method of claim19, wherein the ionic dispersion modulator is a salt.
 22. The method ofclaim 19, wherein the ionic dispersion modulator is an inorganic salt isselected from the group consisting of a magnesium salt, a calcium salt,a lithium salt, a potassium salt, a sodium salt and mixtures thereof.23. The method of claim 19, wherein the ionic dispersion modulator is anorganic salt is selected from the group consisting of a citrate salt, asuccinate salt, a fumarate salt, a malate salt, maleate salt, a tartratesalt, a glutarate salt, a lactate salt and mixtures thereof.
 24. Themethod of claim 18, wherein the pharmaceutically acceptable excipientcomprises a water soluble spacer.
 25. The method of claim 24, whereinthe water soluble spacer is in an amount from about 2% to about 60%,w/w, based on the weight of the solid particles.
 26. The method of claim24, wherein the water soluble spacer is a saccharide or an ammoniumsalt.
 27. The method of claim 26, wherein the saccharide is selectedfrom the group consisting of fructose, sucrose, glucose, lactose,mannitol and mixtures thereof.
 28. The method of claim 18, wherein thedisintegrant is selected from the group consisting of cross-linkedsodium carboxymethylcellulose, crospovidone and any combinations ormixtures thereof.
 29. The method of claim 18, wherein the surfactant isa polysorbate.
 30. The method of claim 18, wherein the plasticizer ispolyethylene glycol.
 31. The method of claim 1, incorporated into atablet or capsule, wherein the dosage form provides a ratio of meanblood plasma fed AUC_((0-τ)) to fasted AUC_((0-τ)) from about 1:1 toabout 4:1.
 32. The method of claim 1, wherein the dosage form provides aratio of mean blood plasma fed Cmax to fasted Cmax from about 1.5:1 toabout 7:1.
 33. The method of claim 1, wherein the particles have avolume weighted median diameter (D50) from about 50 nm to about 1000 nm,and the dosage form provides a mean blood plasma AUC 0-24 hours fromabout 100 to about 375 ng*h/ml when a dose of 200 mg to 500 mg of theganaxolone is orally administered to adult subjects in the fasted state.34. The method of claim 1, wherein the dosage form provides a mean bloodplasma Cmax from about 25 to about 70 ng/ml when a dose of 200 mg to 500mg of the ganaxolone is orally administered to adult subjects in thefasted state.
 35. The method of claim 1, wherein the dosage formproviding a mean blood plasma AUC (0-48) hours from about 400 to about1200 ng*h/ml when a dose of 200 mg to 500 mg of the ganaxolone is orallyadministered to adult subjects in the fed state.
 36. The method of claim1, wherein the dosage form providing a mean blood plasma Cmax from about60 to about 250 ng/ml when a dose of 200 mg to 500 mg of the ganaxoloneis orally administered to adult subjects in the fed state.
 37. Themethod of claim 1, wherein the dosage form provides a mean blood plasmaCmax/Cmin ratio of not greater than about 4 to 1 at steady state with adose of 200 to 500 mg ganaxolone to adult subjects in the fed or fastedstate.
 38. The method of claim 1, wherein the solid dosage form is animmediate release dosage form.
 39. The method of claim 1, wherein thesolid dosage form is a controlled release dosage form.
 40. The method ofclaim 39, wherein the particles are incorporated into an oral soliddosage form comprising (i) a controlled release component comprising afirst portion of the stabilized particles; and a controlled releasematerial, and (ii) an immediate release component comprising a secondportion of the stabilized particles, the first and second portion ofstabilized particles having a volume weighted median diameter (D50) offrom about 50 nm to about 500 nm.
 41. The method of claim 40, whereinthe ratio of ganaxolone in controlled release to immediate release isfrom about 4:1 to about 1:4.
 42. The method of claim 39, wherein dosageform provides a therapeutic effect for about 8 to about 24 hours afteradministration.
 43. The method of claim 1, wherein the complexing agentis in an amount from about 0.05% to about 5%, w/w, based on the weightof the solid particles.
 44. The method of claim 1, wherein thecomplexing agent comprises methylparaben or a salt thereof.
 45. Themethod of claim 1, wherein the complexing agent comprises benzoic acidor a salt thereof.
 46. The method of claim 1, wherein the complexingagent comprises methyl anthranilate.
 47. The method of claim 1, whereinthe effective amount of solid stabilized particles include from about200 mg to about 800 mg ganaxolone.
 48. The method of claim 1, furthercomprising incorporating the solid stabilized particles into an oralsolid dosage form comprising from about 200 mg to about 800 mgganaxolone prior to administration to said human patients.
 49. A methodof treating patients, comprising administering to human patients in needof treatment for a central nervous system disorder selected from thegroup consisting of epileptic seizures, infantile spasms, anxiety,stress, panic, depression, postpartum depression, insomnia, premenstrualsyndrome, post-traumatic stress disorder, substance abuse withdrawal,hypertension, pain, migraine headache, headache associated with pre- andperi-menstrual period, Neimann Pick disease Type-C and Mucolipidosistype IV lipid accumulation, mucolipidosis Type IV lipid accumulation,AIDS-related dementia, Alzheimer's disease, Huntington's disease, andParkinson's disease, comprising administering an effective amount ofsolid stabilized particles comprising ganaxolone, a hydrophilic polymer,a wetting agent, and an effective amount of a complexing agent which isa small organic molecule having a molecular weight less than 550 andcontaining a moiety selected from the group consisting of a phenolmoiety, an aromatic ester moiety and an aromatic acid moiety, whereinthe stabilized particles have a volume weighted median diameter (D50) ofthe particles is from about 50 nm to about 500 nm and the complexingagent being present in an amount from about 0.05% to about 5% w/w basedon the weight particles of the solid.
 50. A method of treating patients,comprising administering to human patients in need of treatment for acentral nervous system disorder an effective amount of solid stabilizedparticles comprising ganaxolone, a hydrophilic polymer, a wetting agent,and an effective amount of a complexing agent selected from the group ofsmall organic molecules having a molecular weight less than 550 andcontaining a moiety selected from the group consisting of a phenolmoiety, an aromatic ester moiety and an aromatic acid moiety, thestabilized particles having a volume weighted median diameter (D50) ofthe particles from about 50 nm to about 500 nm.
 51. The method of claim50, wherein the ganaxolone is present in an amount greater than 50% toabout 80%, based on the weight of the particles.
 52. The method of claim48, wherein the particles are incorporated into a dosage form selectedfrom the group consisting of a tablet or capsule.
 53. The method ofclaim 50, wherein the complexing agent is selected from the groupconsisting of parabens, benzoic acid, methyl anthranilate, andpharmaceutically acceptable salts thereof and mixtures thereof.
 54. Themethod of claim 53, further comprising incorporating the solidstabilized particles into an oral solid dosage form comprising fromabout 200 mg to about 800 mg ganaxolone prior to administration to saidhuman patients.